Regressions were of considerable importance in the Quaternary history of the Capsian Sea. Studies carried out by the Laboratory of Marine Geomorphology (Geographic Faculty of the Moscow State University) revealed a series of deep regressions, when not only North Caspian shallows but almost the whole surface of the Caspian shelf emerged. Each regression is proved to be a complicated event, developed through many phases, with alternating changes of level. The present-day floor relief was modeled to a large extent during regressions.