Yuzhnoye 1000-km range submarine-launched ballistic missile. According to Przybilski, it was related to the light ICBM later designated R-26/8K66.

The R-15 missile was a Yangel design intended for use aboard VMF naval ships and submarines. A 17 August 1956 authorised work on the design, and the draft project was completed in December 1957. However no orders for full-scale development or production were forthcoming.