The idea of founding Yerevan Zoo comes from the 1930’s of the 20th century which, however, was established only in 1940 in compliance with the decision of the Presidium of the Supreme Soviet of Armenia. It was decided that Yerevan Zoo will take up an area of about 3 hectares. Initially, there were around twenty animals and birds in the Zoo which were acquired during the 12th State Zoological Exhibition in Yerevan. From 1941 to 1945 Yerevan Zoo was tasked to start the capital construction works of the park and preserve Zoo species.
In 1945-1946 Yerevan Zoo was home to about 179 animals representing 32 species. Even during the war, Yerevan Zoo was the focus of Moscow’s attention and still received funding for reconstruction and renovation works despite financial issues. In 1954, Yerevan Zoo counted about 332 animals (no available information about species), 95 of which were acquired during the same year. In 1954, around 2500 decorative trees, shrubs and 3000 types of seedlings were planted for the enlargement of the Zoo’s green areas. Yet, because of the absence of irrigation water in the Zoo, most of the new planted trees couldn’t survive. In 1954 the Yerevan Zoo counted 104 foremen, the department of Science and Education was operating permanently. In order to improve the scientific qualifications and skills of the Zoo’s department heads, a number of scientific workshops had been held in the Institute. In 1954, there were 4 departments in Yerevan Zoo: Aqua-terrarium department, Bird department, Predator department and Hoofed-stock department. Already in 1980, the Yerevan Zoo was home to around 350 species of animals (no information available about the quantity), which decreased to 260 at the beginning of 1990.