Abstract: Annual variations in percentage of egg-carrying females were taken as a means of studying the reproductive cycle of the fresh-water prawn,Macrobrachium nipponense.The materials were mainly collected from fish ponds of Kwangtung Province, South China. Results indicate that the reproductive season of this prawn lasts from early dareh to late November. The number of egg-carrying females reaches a peak between avid-April and mid-May, and again in mid-September when the peak is less obvious.