Ristić wrote his most boldest compositions, including those in quarter- and sixth-tone systems, during his studies. He is though, best known for his nine symphonies and other orchestral works, such as Sinfonietta, Man and war (symphonic poem), Symphonic movement, Suita giocosa, Symphonic variations, Burlesque, Seven bagatelles, The Suite, Three little pieces, Three polyphonic studies, and The Gallop. Along with his symphonic compositions, he wrote a number of concertante works, including Concerto for violin, two concertos for piano, Concerto for clarinet, Concerto for trumpet, Concerto for orchestra, and Concerto for chamber orchestra. His chamber oeuvre in the semitone system consists of notable works such as the five-string quartets, Wind quintet, Sonata for two violins and piano, two sonatas for violin and piano, Sonata for viola and piano, Duet for violin and piano, Duet for violin and viola, and twenty-four fugues for various instrumental ensembles. Among Ristić's quarter-tone works are: Suite for four trombones, the Septet, Suite for ten string instruments, Sonata for solo violin, and his Duet for violin and cello, which is based upon the sixth-tone microtonal system. Ristić also composed stage music for the ballets Cinderella and The Tyrant (unfinished). His works Through the blizzard, The Poplar, The Death of Smail-aga Čengić, and A Song about the hawk, for narrator and chamber or large orchestra, aligned him with a few Serbian composers who fostered the melodrama genre. Ristić left behind a certain number of folk-song and dance arrangements and orchestrations of compositions by Josif Marinković and Isidor Bajić.
The Second symphony from 1951 represents a paradigmatic example of Ristić's compositional and technical skillfulness. Realized with limited means of expression, the symphony is oriented toward a balanced and perspicuous form achieved through transparent melodic content and functional harmonic relationships. The first, upbeat movement embraces a lyrical theme, defining in its further unfolding the contours of a sonata form. The second movement represents simulation of a serenade with a grotesque gesture embodied in the theme's orchestration, delivered by clarinet accompanied by tuba and bassoon. Featuring odd meters, the Scherzo and Trio imply folk origins, though lacking any unambiguous melodic relationships with a certain folk tune. The symphony's finale develops as a modernist fugue, in which Ristić showcased his conduct of contrapuntal skills (inversions, augmentations, and stretti). Ethereal but effective orchestration and receptiveness of performers and audience, led to international performances of this work (Geneva, orchestra Suisse romande). In 1951, when the symphony was premiered (September 5, 1951, Symphonic Orchestra of the People's Republic of Serbia, conductor Živojin Zdravković), a transition from the dominant socialist realism toward (moderately socialist) modernist—socialist aestheticism took place and "the Second symphony marked the beginning of the 'new epoch' in Serbian music and culture at large" (Mikić 2009, 119). In its structural aspects, Ristić's Second symphony corresponded with the unfolding cultural changes. The symphony's neoclassic expression represents a fostering of tradition of 'healthy' classicism, contrary to the daily vulgarization of art for political purposes. Lacking the programmatic underpinnings, but skillfully developed in terms of canonic craft and simulation of certain models with folkloristic connotation (Scherzo in 5/8 and Trio in 7/8 meter), by its completeness and wholeness, this symphony does not oppose the then governing doctrine, while at the same time it represents a work of modern expression. By its optimistic spirits the Second symphony embodies the momentum of transition of the entire Yugoslav society from a Warsaw Pact country to one of self-governed socialism.
Suita giocosa, but particularly The Seven bagatelles for orchestra, both underscore Ristić's "optimism"; "with clear forms and free but still present tonality and clarity of polyphonic procedures (...) these works carry extraordinary communicativeness" (Bergamo 1977, 80). Peričić states that Ristić's Bagatelles are "humorous, of clear formal structure, and transparent sound," and labels the composer "a master of neoclassic expression," to whose works are attributed "gaiety, lyricism, and amiable humor," but always "rationally controlled" (Peričić 1969, 471-72). Evoking his Second symphony's Scherzo, Ristić in Bagatelles utilizes 5/8 meter, thus "implying folklore," but also includes a very important modernist epithet which by its "unusual harmonies" speaks about the composer's "individuality" and "contemporaneousness" (Peričić 1969, 472). The published reviews of Ristić's works at the time of their performances reinforce "the closeness with the man of our reality," "the results yielded by the synthesis of talent, healthy life outlook, and studious, hard work," and a "sound orchestral style in our music" (Bergamo 1977, 80).
In the Third symphony, from the position acquired in his previous works, Ristić selects and re-adopts certain procedures from his student compositions. The Symphony is dedicated to the 20th anniversary of the Revolution, and was performed on the eve of the celebration of the Uprising Day, 6 July 1961, and then at the concert of the Belgrade Philharmonic with conductor Živojin Zdravković. The same year it was conferred the Belgrade October Award. The example of the Third symphony offers numerous compromises characteristic for socialist aestheticism. Expressively far from soc-realism, this work is indeed dedicated to the 20th anniversary of the Revolution. But it does not feature quotations of the songs from the National Liberation War (Narodnooslobodilacka borba, NOB) or procedures known from the 1940s. The only connection with the Revolution is found in the movements' subtitles (Youth—Unrests—Occupation—New world (Mladost—Nemiri—Okupacija—Novi svet)), but in synthesis with Ristić's biography. The "classic" four-movement symphonic cycle with the "appropriate" order of movements (second movement Scherzo, third movement slow) is realized with "contemporary" language. The language "contemporaneousness" however, is not unambiguous since it does not pertain to dodecaphony or tonal means, while at the same time both the procedures with twelve tones and clear "tonal" centers exist in the work. Here, Ristić also demonstrated his contrapuntal and orchestration skills, though without indication of communicating an extra musical narrative. This composition does not contain a "strict, determined program," but, as Peričić states "it operates by its sole musical content." The "non-discursive" trait of this symphony is emphasized by its traditional four-movement formal plan: Allegro moderato—Vivace, Come una Marcia funebre, Tempo I—Andante mosso— Allegro assai, in which individual movements follow the sonata form (first and fourth movements), and binary—ternary architectural patterns (second and third movements).
Concerto for piano and orchestra from 1954 is conceived simply, without the usual virtuosity. The micro plan of the work, with order of movements—fast-slow-fast—does not deviate from traditional concept. Ristić here also utilizes C. Franck's cyclical principle. Following the first subject in C-major, the appearance of the second subject in A-flat major, as well as meter changes in the second movement (4/4, 5/4, 4/4, and 5/4) depart from "classical" solutions. The second, lyrical movement begins with a polyphonic excerpt with meter changes, thus implying folk connotations. The third movement, featuring chords brisker then used previously, flows in an upbeat motion.
The oeuvre of Milan Ristić additionally includes Concerto for violin (1944), Concerto for clarinet (1964), the Fourth (1966), Fifth (1967), Sixth (1968), Seventh (1972), Eighth (1974), and Ninth (1976) symphonies, Concerto for piano from 1973, and Concerto for trumpet from 1978.
