Konstantin Iliev graduated from the State Academy of Music in 1946 majoring in Composition under Professor Pancho Vladigerov , conducting under Professor Marin Goleminov and Violin under Professor Vladimir Avramov. In 1946-47 he specialised at the Prague Music Academy in conducting under Professor V. Talih, composition under Y. Ridki, and attended quadritone composition classes given by Professor Alois Haba. In 1947 he returned to Bulgaria. For a while he worked as a musicologist at the Bulgarian National Radio. He founded the State Symphony Orchestra in Ruse (1947-48). He conducted the ballet of the Sofia Opera (1948-49), was chief conductor of the State Symphony Orchestra and of the National Opera in Ruse (1949-52); then chief conductor of the Varna Symphony Orchestra (1952-56). Since 1956 (with interruptions) he was conductor and chief conductor of the Sofia Philharmonic. In 1967 he was appointed Professor of Orchestral Conducting at the State Academy of Music. In 1969 he left the Sofia Philharmonic and until 1971 he made a series of concerts and recordings for the recording company Balkanton with the orchestra of the State Academy of Music. During the period 1971-72 and 1978-84 he was re-appointed chief conductor of the Sofia Philharmonic. From 1972 to 1978 he lived in Dobrich, where he founded the Chamber Music Festival. The last performance of Konstantin Iliev as a conductor was in 1988 in Ruse. Konstantin Iliev’s art of conducting won recognition in many countries in Europe, America and Asia. He occupied a significant role in spreading the 20th century music. He recorded for the Bulgarian National Radio, Balkanton and foreign radio stations.

He is one of the most significant contemporary Bulgarian composers, which work has been connected with the Bulgarian music vanguard. He wrote in a variety of genres and composed two operas and a ballet; cantatas and oratorios; six symphonies and other works for symphony orchestra; seven Tempi Concertati for various instrumental ensembles; four string quartets; a wind quintet and other chamber and solo music; five songs for voice and piano; choral music for various ensembles; film and theatre music.

He wrote three books, and also articles and studies.

Stage music:
Operas:
The Boyana Master (premiered in Sofia, 1962);
Deer’s Kingdom (premiered in Ruse, 1974).

Ballet:
Broadcloth Jacket (1958, not staged).

Vocal and instrumental:
Oratories:
Eulogy to Konstantin Cyril Called the Philosopher for solo tenor and bass, mixed choir and instruments (1970).

Cantatas:
September 1923 for soloists, choir and orchestra (1963);
The Seasons for female voices choir and orchestra (1963);
He Was Supposed to Come for tenor, reader, mixed choir, strings, piano, flute, two trumpets, two trombones and percussion (1969);

The Marvelous Horo Suite for female voices choir, wind quintet and piano (1956);

Poem to the Deceased, Dedicated to the Living Ones for children’s choir, three mixed choirs, soloists, readers, instruments and loudspeakers (1972);

Spring Festivities for soprano, tenor, female voices choir, male voices choir and mixed choir, two grand pianos and percussion (1975);

Christmas for female and male voices choirs, tenor, bass, speaker, two grand pianos and percussion (1984).

Works for symphony orchestra:
Symphonies:
N1 (1947); N2 (for wind instruments) (1951); N3 (1954); N5 (1959); N6 (1984).

Sonatina for orchestra (1944-45); Divertimento (1949).

Symphonic Poem Song of the Human Joy (1951); Variations (1952-53); Waltz (1959); Fragments (1968); Musical Moments (1972); Bucoliques (1977); Games (1980); Medley (1980); LI in Memoriam (1981-82); Childrens Birds (1982); Eyes of Night (1987).

Concertino for flute and orchestra (1946); Concerto for violin and orchestra (1971).

For string orchestra:
Symphony N4 for bass and string orchestra (1958). Two Improvisations (1948); Concerto Grosso for string orchestra, piano and percussion (1950); Retrospections (1982).

Chamber Music:
Tempi Concertati I-VII: N1 for 13 strings or string quartet and string orchestra (1968); N2 for flute, harpsichord and 12 strings (1975); N3 for solo violoncello and 3 groups of percussion instruments (1977); N4 for violin, violoncello, 2 groups of percussion instruments and celesta (1980); N5 for 14 wind instruments (1981); N6 for flute, violoncello and harp (1985); N7 for piano, clarinet and orchestra (1988, unfinished).

Four Pieces for flute, clarinet, violin, viola and violoncello (1953);

Six Pieces for oboe, French horn, violin, viola and violoncello (1953);

Wind quintet (1943).

String Quartets:
N1 (1948); N2 (1951-52); N3 (1955); N4 (1956).

Three Pieces for two clarinets and bass clarinet (1953);
Five Pieces for oboe, bassoon and clarinet (1954);
Piano Trio (1976).

Sonatas for:
two violins (1953); violin and viola (1953); violin and violoncello (1953).

Comments for violoncello and piano (1968);
Ad Libitum for viola and violoncello (1978);
Seven Bagatelles for clarinet and violoncello (1987).

Solo pieces:

Three Capriccios for solo clarinet (1959);
Solo per ViolinGio (1987);
Sonata for solo violin in 1/4 ton (1974);
Sonata for solo violoncello (1953);
Solo per VenziCello (1987).

For piano:
Two pieces for children (1946);
Small suite for piano in tone (1947);
Children’s Birds (1963);
Movements (1964);
Album’s Page (1987);
Solo per ClaviStella (1988).

Vocal music:

For voice and piano:
Six Songs, lyrics by S. Krasinsky (1944-45);
Do You Remember the Quiet Street, lyrics by V. Dinova (1946);
Bulgarian Language, lyrics by Ivan Vazov (1950);
Summer – vocal cycle after Elisaveta Bagriana (1954);
Reflections Cantata, lyrics by L. Hughes.

Choral music:
For female voices choir:
Before the Storm after Veselin Hanchev and Night after a poem by Asen Raztsvetnikov (1962);
The Forest and the Birds – cantata without words (1976);
The Doe, lyrics by Mladen Isaev (1981).

For mixed choir:
Peasant Cantata, lyrics by Asen Raztsvetnikov (1965);
Green Clouds, lyrics by S. Krasinski (1965);
Two Poems after Atanas Dalchev (1966);
Three Improvisations after Don Quixote and Working-bee Songs, both on poems by Asen Raztsvetnikov (1966);
Zadyavki (Girds) (1972) and Tihi pesni (Quiet Songs) (1974), both on poems by Nikolay Liliev.

Film music to:
Our Land (1952); Adam’s Rib (1956); The Gerak Family (1957); Poor Man’s Joy (1958); Roads: Another Kind of Happiness (1959); The Golden Tooth, directed by A. Marinovich (1962); Beyond the Horizon, directed by Z. Zhandov (1959).

Selected books (published in Bulgarian):
Lubomir Pipkov (Sofia, 1958); Word And Action (Sofia, 1997); Lazar Nikolov (Plovdiv, 2002).

Selected literature on him (in Bulgarian):
Konstantin Iliev. Music Work. Catalogue (Sofia, 2000).