Development of the aircraft began in January 1960 under the specification Isdeliye (Изделие, Product) L by Tupolev OKB and was led by Nikolay Blazenkov. The first flight was made by Ivan Sukhomlin in the year 1962. The first Tu-126 entered service in the year 1965. The main role was airborne reconnaissance, being supported by the large rotodyme. But it was also used as a flying command center to coordinate the troops on the ground and in the air. To improve the aircraft's maximum flight endurance, it was designed to be able to perform air-to-air refueling. Unfortunately the Tu-126 had a massive problem; the large contra-rotating turboprop propellers caused interferences on the radar screen. So that the aircraft was immediately replaced after the Beriyev A-50 entered service in the year 1985.