The Symphony No. 1 in D major by Gustav Mahler was mainly composed between late 1887 and March 1888, though it incorporates music Mahler had composed for previous works. It was composed while Mahler was second conductor at the Leipzig Opera in Germany. Although in his letters Mahler almost always referred to the work as a symphony, the first two performances described it as a symphonic poem and as a tone poem in symphonic form, respectively. The work was premièred at the Vigadó Concert Hall in Budapest, Hungary, in 1889, but was not well-received. Mahler made some major revisions for the second performance, given at Hamburg, Germany, in October 1893; further alterations were made in the years prior to the first publication, in late 1898. Some modern performances and recordings give the work the title Titan, despite the fact that Mahler only used this label for the second and third performances, and never after the work had reached its definitive four-movement form in 1896. Mahler conducted more performances of this symphony than of any of his later works.

The Symphony No. 10 in F-sharp major by Gustav Mahler was written in the summer of 1910, and was his final composition. At the time of Mahler's death, the composition was substantially complete in the form of a continuous draft, but not fully elaborated or orchestrated, and thus not performable. Only the first movement is regarded as reasonably complete and performable as Mahler intended. Perhaps as a reflection of the inner turmoil he was undergoing at the time (Mahler knew that he had a failing heart and that his wife had been unfaithful), the 10th Symphony is arguably his most dissonant work.

The Symphony No. 2 in C minor by Gustav Mahler, known as the Resurrection Symphony, was written between 1888 and 1894, and first performed in 1895. This symphony was one of Mahler's most popular and successful works during his lifetime. It was his first major work to establish his lifelong view of the beauty of afterlife and resurrection. In this large work, the composer further developed the creativity of "sound of the distance" and creating a "world of its own", aspects already seen in his First Symphony. The work has a duration of 80 to 90 minutes, and is conventionally labelled as being in the key of C minor; the New Grove Dictionary of Music and Musicians labels the work's tonality as C minor–E♭ major. It was voted the fifth-greatest symphony of all time in a survey of conductors carried out by the BBC Music Magazine.

The Symphony No. 3 in D minor by Gustav Mahler was written in sketch beginning in 1893, composed primarily in 1895, and took final form in 1896. Consisting of six movements, it is Mahler's longest composition and is the longest symphony in the standard repertoire, with a typical performance lasting around 95 to 110 minutes. It was voted one of the ten greatest symphonies of all time in a survey of conductors carried out by the BBC Music Magazine.

The Symphony No. 4 in G major by Gustav Mahler was composed from 1899 to 1900, though it incorporates a song originally written in 1892. That song, "Das himmlische Leben" ("The Heavenly Life"), presents a child's vision of heaven and is sung by a soprano in the symphony's Finale. Both smaller in orchestration and shorter in length than Mahler's earlier symphonies, the Fourth Symphony was initially planned to be in six movements, alternating between three instrumental and three vocal movements. The symphony's final form—begun in July 1899 at Bad Aussee and completed in August 1900 at Maiernigg—retains only one vocal movement (the Finale) and is in four movements: Bedächtig, nicht eilen (sonata form); In gemächlicher Bewegung, ohne Hast (scherzo and trio); Ruhevoll, poco adagio (double theme and variations); and Sehr behaglich (strophic variations). The premiere was performed in Munich on 25 November 1901 by the composer and the Kaim Orchestra, but it was met with negative audience and critical reception over the work's confusing intentions and perceived inferiority to the more well-received Second Symphony. The premiere was followed by a German tour, a 1901 Berlin premiere, and a 1902 Vienna premiere, which were met with near-unanimous condemnation of the symphony. Mahler conducted further performances of the symphony, sometimes to warm receptions, and the work received its American and British premieres in 1904 and 1905. The symphony's first edition was published in 1902, but Mahler made several more revisions up until 1911. After Mahler's death, the symphony continued to receive performances under conductors such as Willem Mengelberg and Bruno Walter, and its first recording is a 1930 Japanese rendition conducted by Hidemaro Konoye that is also the first electrical recording of any Mahler symphony. The musicologist Donald Mitchell believed the Fourth and its accessibility were largely responsible for the post-war rise in Mahler's popularity. The symphony uses cyclic form throughout its structure, such as in the anticipations of the Finale's main theme in the previous three movements. The first movement has been characterized as neoclassical in style, save for its complex development section. The second movement consists of scherzos depicting Death at his fiddle, which are contrasted with Ländler-like trios. The third movement's two themes are varied alternately before reaching a triple forte coda, and the Finale comprises verses from "Das himmlische Leben" sung in strophes that are separated by refrains of the first movement's opening. Certain themes and motifs in the Fourth Symphony are also found in Mahler's Second, Third, and Fifth Symphonies.

C-sharp minor is a minor scale based on C♯, with the pitches C♯, D♯, E, F♯, G♯, A, and B. Its key signature consists of four sharps. The C-sharp natural minor scale is: Changes needed for the melodic and harmonic versions of the scale are written in with accidentals as necessary. The C-sharp harmonic minor and melodic minor scales are: Its relative major is E major. Its parallel major, C-sharp major, is usually written instead as the enharmonic key of D-flat major, since C-sharp major’s key signature with seven sharps is not normally used. Its enharmonic equivalent, D-flat minor, having eight flats including the B, has a similar problem. Therefore, C-sharp minor is often used as the parallel minor for D-flat major. (The same enharmonic situation occurs with the keys of A-flat major and G-sharp minor, and in some cases, with the keys of G-flat major and F-sharp minor, and with the keys of E-flat major and D-sharp minor.)

The Symphony No. 6 in A minor by Gustav Mahler is a symphony in four movements, composed in 1903 and 1904, with revisions from 1906. It is sometimes nicknamed the Tragic ("Tragische"), though the origin of the name is unclear.

The Symphony No. 7 by Gustav Mahler is a symphony in five movements composed in 1904–05, sometimes referred to by the title Song of the Night (German: Lied der Nacht), which was not the composer's own designation. Although the symphony is often described as being in the key of E minor, its tonal scheme is more complicated. The symphony's first movement moves from B minor (introduction) to E minor, and the work ends with a rondo finale in C major. Thus, as Dika Newlin has pointed out, "in this symphony Mahler returns to the ideal of 'progressive tonality' which he had abandoned in the Sixth". The complexity of the work's tonal scheme was analysed in terms of "interlocking structures" by Graham George.

The Symphony No. 8 in E-flat major by Gustav Mahler is one of the largest-scale choral works in the classical concert repertoire. As it requires huge instrumental and vocal forces it is frequently called the "Symphony of a Thousand", although the work is normally presented with far fewer than a thousand performers and Mahler greatly disapproved of the name. The work was composed in a single inspired burst at his Maiernigg villa in southern Austria in the summer of 1906. The last of Mahler's works that was premiered in his lifetime, the symphony was a critical and popular success when he conducted the Munich Philharmonic in its first performance, in Munich, on 12 September 1910. The fusion of song and symphony had been a characteristic of Mahler's early works. In his "middle" compositional period after 1901, a change of style led him to produce three purely instrumental symphonies. The Eighth, marking the end of the middle period, returns to a combination of orchestra and voice in a symphonic context. The structure of the work is unconventional: instead of the normal framework of several movements, the piece is in two parts. Part I is based on the Latin text of Veni creator spiritus ("Come, Creator Spirit"), a ninth-century Christian hymn for Pentecost, and Part II is a setting of the words from the closing scene of Goethe's Faust. The two parts are unified by a common idea, that of redemption through the power of love, a unity conveyed through shared musical themes. Mahler had been convinced from the start of the work's significance; in renouncing the pessimism that had marked much of his music, he offered the Eighth as an expression of confidence in the eternal human spirit. In the period following the composer's death, performances were comparatively rare. However, from the mid-20th century onwards the symphony has been heard regularly in concert halls all over the world, and has been recorded many times. While recognising its wide popularity, modern critics have divided opinions on the work; Theodor W. Adorno, Robert Simpson, and Jonathan Carr found its optimism unconvincing, and considered it artistically and musically inferior to Mahler's other symphonies. Conversely, it has been compared by Deryck Cooke to Ludwig van Beethoven's Symphony No. 9 as a defining human statement for its century.

The Symphony No. 9 by Gustav Mahler was written between 1908 and 1909, and was the last symphony that he completed. A typical performance takes about 75 to 90 minutes. A survey of conductors voted Mahler's Symphony No. 9 the fourth greatest symphony of all time in a ballot conducted by BBC Music Magazine in 2016. As in the case of his earlier Das Lied von der Erde, Mahler did not live to see his Symphony No. 9 performed. Though the work is often described as being in the key of D major, the tonal scheme of the symphony as a whole is progressive. While the opening movement is in D major, the finale is in D♭ major.

The Symphony No. 2 in C minor by Gustav Mahler, known as the Resurrection Symphony, was written between 1888 and 1894, and first performed in 1895. This symphony was one of Mahler's most popular and successful works during his lifetime. It was his first major work to establish his lifelong view of the beauty of afterlife and resurrection. In this large work, the composer further developed the creativity of "sound of the distance" and creating a "world of its own", aspects already seen in his First Symphony. The work has a duration of 80 to 90 minutes, and is conventionally labelled as being in the key of C minor; the New Grove Dictionary of Music and Musicians labels the work's tonality as C minor–E♭ major. It was voted the fifth-greatest symphony of all time in a survey of conductors carried out by the BBC Music Magazine.