The ZSU-37-2 Yenisei ("Yenisey", GRAU index 2A1) was an experimental self-propelled anti-aircraft gun developed in the Soviet Union in the late 1950s.

The decree ordered that work be started on new types of rapid-firing self-propelled anti-aircraft guns, which were to be named "Shilka" and "Yenisei".

[3] Results showed that the Yenisei had an effective firing zone similar to that of the ZSU-57-2, while fulfilling the requirement from the Council of Ministers to "cover tank forces in all kinds of battles, and from aerial attacks at altitudes up to 3,000 m".

[2] Concluding from the results from state trials, the Yenisei was reassigned the task of defending the 2K11 Krug and the 2K12 Kub from attacks from the missiles' launch dead zones.

A gas turbine designed by NAMI fed electricity to on-board electronics, which enabled quick transition to combat readiness even under low-temperature circumstances, as the radar needed to be properly heated up prior to use.

The 500P autocannon was designed in OKB-16, headed by Alexander Nudelman, firing dedicated 37 mm cartridges with unique ballistic qualities.

The Yenisei was guided with the 1A11 "Baikal" jamming-resistant radar station operating in the centimeter band, with a wavelength of around 3 cm.

However, it was found during state trials that neither the "Tobol" radar on the Shilka nor the "Baikal" on the Yenisei could discover aerial targets effectively on its own.