Attempts on cryopreservation of spermatozoa have been made in penaeid shrimp, Penaeus indicus. Viable spermatozoa could be preserved successfully for a period of 60 days at -35°C and -196°C. Among several cryoprotectants used, a combination of DMSO (5 %) and glycerol (5 %), DMSO (5 %) and trehalose (0.25M) showed best viability rate (75 to 80 %) in freeze, thawed spermatozoa. Activational changes in spermatozoa during acrosome reaction after induction with egg water have also been recorded. The importance of cryogenic storage of spermatozoa is discussed.