The aim of study was to determine the dates of breeding and sexual maturity for Marsupenaeus japonicus in Lattakia coast as introduce for hatching and culturing it. The specimens were collected from the sea water of Ibn-Hany area at the north of Lattakia, during the period November 2010 to October 2011 once or twice monthly. In vitro study included distinguishes males and females, morphometric measurements and weights for all individuals. The genital maturity stage was determined externally and through histological sections.