Melikyan also composed numerous choir compositions, romances, pieces for different instruments, as well as music to films including The Ingenious Peasant.
In 1967, at the age of 20, he entered the composition department of the Yerevan State Conservatory, class of USSR People's Artist, Professor Edvard Mirzoyan.
His works composed during his student years were published by the Conservatory and were performed in Yerevan, Tbilisi, Baku, Kiev and other capitals of the former Soviet republics.
A talented exponent of the Armenian contemporary composition school, Hrachya Melikyan with his new artistic vision and distinctive musical style belongs to the generation of 1960–1970s.
Ghazaros (Lazar) Saryan in his reference letter, dated July 1, 1972, for Melikyan to be accepted as a member of the Union of Composers, wrote "His style is interesting and distinctive/original.
From the time he took up an administrative position in the Union until his last days he played a significant role in promoting his fellow composers’ compositions through organizing concerts and publishing their works.
The variety of compositions of the composer is indicative of his special interest to bring to light the different tones of instrumental timbres that complement one another.
In this context, Hrachya Melikyan's place among the Armenian composers is exceptional not only by the quantity of compositions for woodwind instruments, but also by the variety of timbral characters.
The composer's interest was not limited by genres of chamber music – concerto, quintet, quartet, trio, sonata, sonatina, pieces, etc.
The Quartet was performed shortly after his death, a beautiful piece, but unlike most of his works, very peaceful, a sort of farewell to life.
One day before his departure from life, he signed a contract for publication of his Twelve Pieces for Cello and Piano and the String Quartet with Editions Bim,[4] a Swiss Publishing Company.
In 1995, Melikyan became a laureate of the prize of the "Best Cello Concerto" contest, sponsored by "HOVARTZ" (USA) and the Union of Composers and Musicologists of Armenia.