The operetta and the genre of musical comedy take a special place in the works of Azerbaijani composers. The investigation of the establishment and development of this genre is of great importance for the science of musicology. The creation of this genre took place in different decades of the twentieth century and also had a special impact on the work of other composers. The main task of the genre of operetta is to solve a problem with the help of humor, to show an unexpected flow of events and an unusual attitude of the characters to what is happening. Rauf Gadjiev used the genre of operetta and musical comedy in his works. His works in the genre have gained popularity not only in Azerbaijan but also in post-Soviet countries. The first work of R. Gadjiev, dedicated to the genre of musical comedy from the first days of his career, “Pranks of Students,” dates back to 1940, which corresponds to the student years of the composer. The work was written based on the work of the English playwright Brandon Thomas “Aunt Charley.” The work was the first test of the composer, and R. Gadjiev returned to this genre in 1960. One of his bright operettas is “Romeo is My Neighbor,” the premiere of which took place in Baku under the name “Neighbors.” Soon after this, the work also received great sympathy among the Moscow public. The song “My Lover” (“Sevgilim”), passing as a leitmotif, subsequently continued its independent concert life in the repertoire of outstanding singers. The combination of people from different strata of society, old and young, with different worldviews and ways of thinking, and the depiction of the characters by brilliant music of each image are among the reasons for the high appreciation of the operetta of R. Gadjiev. Far from musical comedies and operetta styles on the stage of the Azerbaijan Musical Theater, the composer managed to create a new style that used modern musical expressions and delighted the audience. In 1963, the composer presented his new work to the Moscow Theater. The operetta “Cuba, My Love” was dedicated to the 5th anniversary of the Cuban Revolution. The courage exhibited by the Cuban people in achieving their freedom was met with great enthusiasm in Soviet countries, and the plot of the operetta was dedicated to the struggle of the Cuban people for freedom. This theme, which does not correspond to the operetta genre, posed a number of problems in front of the composer, but he was able to justify himself by comparing serious and comic, humorous and satirical, lyrical characters. In 1969, the composer presented the work “Don’t Hide Your Smile,” and in 1971 the operetta “The Fourth Vertebra” in a new style. “Don’t Hide Your Smile” was more of a vaudeville character. Its main feature is the bright national atmosphere. The operetta of the composer “Crossroads” was met with great enthusiasm in 1981. The theme of this work is the revolutionary events of the early twentieth century. However, this theme was presented in a unique way. Although there are no scenes representing these events in the work, they indirectly play an important role. The primary attention in the operetta is paid to ordinary people, who must bear the burden of these events. This is shown in the first act. The overture of the operetta is somewhat different from the traditional one: the polyphony of sound symbols, which combine contrasting images, prevails here, the call for prayer “Ezan,” the factory bell, and a charming song are mixed. This musical number represents the bright face of revolutionary Baku of that time. The image of the city also opens in the market. The main characters live in the middle of this market. A typical home scene presents the first presentation of images. The composer used a wide range of folk song genres. This scene is also typical for the beginning of the main dramatic line of the work. A total of 7 operettas of the composer, 5 of which were staged on the stage of the Moscow Theater, were successful. The contribution of the composer to the development of the genre of operetta and musical comedy is priceless. In his operettas, literary and musical dramaturgy is enriched with new studies. The composer managed to create brilliant musical masterpieces by widely using a variety of pop and jazz music.