Dimitar Sagaev graduated from the State Academy of Music in 1940 majoring in Composition under Professor Pancho Vladigerov, Music Theory and Orchestration under Professor Vesselin Stoyanov and Piano under Professor Panka Pelisek. He worked as music teacher at the Plovdiv Male High School (1941-42), bandmaster (1943-46), Head of Art Music Section of Radio Sofia (1946-49), bandmaster of the wind orchestra at the Ministry of Interior (1949-53), music director at the Bulgarian Radio (1946-49) and director of the Music and Opera Theatres Department of the Ministry of Culture (1952-55). In 1948 he joined the staff of the State Academy of Music teaching Symphony Orchestration and Theory of Music. He became full professor and taught generations of composers, conductors and musicologists. He was awarded high state prizes, orders and medals. In 2002 he was given the title Doctor honoris causa by the State Academy of Music.

His work is important; he wrote in a variety of genres: two operas and two ballets; six oratorios and cantatas; seven symphonies; over 20 instrumental concertos; chamber music, etc. His works are well known abroad. His Concerto for violin and orchestra 2 was performed by Dina Schneidermann and the Dresden Philharmonic, conducted by Kurt Mazur; his String Quartet 2 was performed by the famous French ensemble Parenine.

He authored books, textbooks, etc.

Stage music:
Operas:

Under the Yoke, after the novel by Ivan Vazov (1965);
Tsar Samuil (1973).

Ballets:

The Madar Horseman (1961);
Eagle’s Rock (1978).

Choral-orchestral works:
Oratories:

For soloists, choir and symphony orchestra:

In Such a Time (1966);
Levski (1976);
Urvich (with reader) (1983);
The Artist (1987);
Rakovski – cantata-poem (1993).

For soloists, female voices choir, traditional music choir and wind orchestra:

The Pleven Epic Story (with reader) (1987).

Symphonies:

Symphony N1 for symphony orchestra, female voices choir, soloist and reader (1964);
Symphony N2 for big wind orchestra, male and childrens choir (1977);
Symphony N3 for symphony orchestra, mezzo-soprano, baritone and reader (1979);
Symphony N5 The Samara Banner for symphony orchestra, solo baritone and reader (1981);
Symphony N6 for symphony orchestra, mezzo-soprano and reader (1983).

Works for symphony orchestra:
Symphonies:

Symphony N4 (1980);
Symphony N7 Romantic;
Symphonic Scherzo (1946);
Youth Suite (1952);
Symphonic Dances (1956).

Symphonic poems:

Sofia (1953);
Polyeley na balgarkata (Glorification of the Bulgarian Woman) (1974).

Concertos:

Violin: Concerto N1 (1963); Concerto N2 (1964).

Oboe: Concerto N1 (1966); Concerto N2 (1991);

Concerto for bassoon (1973);
Concerto for flute 1 (1976);
Concerto for horn (1976);
Concerto for violoncello 1 (1977);
Concerto for trombone (1988);
Concerto for trumpet 1 (1989);
Piano: Concerto N1 (1992); Concerto N2 (1994);

Concerto for clarinet, piano, percussion and symphony orchestra (1993);
Concerto for harp (2002).

Works for wind orchestra:
Concerto (1983).

Works for chamber orchestra:
Concertos:

Sextet for two violins, viola, violoncello, clarinet and bassoon (1986);
Kaval;
Harp and violoncello (1999);
Two pianos (2000).

Works for string orchestra:
Concertos:

Concerto for guitar (1995);
Concerto for flute 2 (1996);
Concerto for clarinet 2 (1996);
Concerto for violoncello 2 (1997);
Concerto for tube, soprano, alt and string orchestra (1997);
Concerto for trumpet and string orchestra 2 (1998).

Chamber Music:
Sextet for two violins, viola, violoncello, clarinet and bassoon (1986).

Two wind quintets (1961).

Quartets:

Strings:

Quartet N1 (1946); Quartet N2, Quartet N3 (1962); Quartet N4 (1963); Quartet N5 (1966); Quartet N6 (1977); Quartet N7 (1967). Quartet for harp, oboe, clarinet and bassoon (1962); Quartet for flute, viola, harp and piano (1975); Quartet for flute, violin, viola and violoncello (1980).

Trio for oboe, clarinet and bassoon (1961);
Sirynx Trio for flute, oboe and bassoon (1978).

Sonatas for:

Sonata for violin and piano; Sonata for flute and piano; Sonata for clarinet and piano; Sonata for bassoon and piano; Sonata for oboe and piano; Sonata for horn and piano; Sonata for trumpet and piano; Sonata for trombone and piano; Sonata for double bass and piano (1947-1989).

Cantilena for violin and harp (2002).

Six Capriccios for violin solo (1964).

Two Nocturnes for harp (1998).

For piano:

6 preludes (1963); 4 pieces (1994); 4 sonatas (1993-94) and others.

Selected books (published in Bulgarian):
Music Instruments (Sofia, 1974);
A Practical Course in Symphony Orchestration, Vol. 1 (Sofia, 1966); Vol. 2 (Sofia, 1973; second edition 1987);
A Guide to Wind Orchestration (Sofia, 1965; second edition 1975);
Autobiography (Sofia, 1978);
Picture Gallery – Music Creators of Our Time (1981;1985);
Sasha Popov and the Bulgarian Symphonism (Sofia, 1997).