Assen Dimitrov graduated from the Prague Conservatory where he studied Composition under Vaclav Novak and Spilka (1911-15). In 1915 he returned to Bulgaria. In 1923 he was appointed artistic secretary of the Sofia Opera, where he served as accompanist, chorus master and conductor up to 1959. He contributed a lot to the recognition of the artistic team of the Sofia Opera. During his 35-year practice as opera conductor, he staged and conducted 30 works by Bulgarian and foreign authors. During the same period he was also Chief Artistic Director and Conductor of the Gusla Choir (1930-60). He conducted concerts of the Sofia Philharmonic and of the Sofia Opera Orchestra. He took part in chamber ensembles as a pianist. His academic activity began in 1924-25. He was Head of the Orchestration and Chamber-Instrumental Class of the State Academy of Music. In 1949 he began teaching Orchestral and Choral Conducting at the State Academy of Music. He taught the famous Bulgarian conductors Dobrin Petkov, Ruslan Raychev, Emil Glavanakov and others. He was awarded the Polish Order for Art and Science, as well as national orders and distinctions.

He is the author of songs for male voices choir. When he was a student he also composed orchestral, chamber and vocal works.

Works for symphony orchestra:
Hadji Dimitar; A Violinist Couldn’t Provide for a Family (1921, Prague)

Chamber Music:
String Quartet.

For piano: Miniatures.

Vocal music: Songs after poems by P. Slaveykov.