Spermatozoa of striped bass Morone saxatilis were successfully cryopreserved, retaining fertilizing capacity for up to 2 years. Spermatozoa in 14 extenders, in combination with three concentrations of four cryoprotectants at various sperm : medium ratios, were frozen at different rates and tested. Best results were obtained with extender “OH-189” (7.30 g NaCl, 0.38 g KCl, 0.23 g CaCl2˙2H2O, 5.00 g NaHCO3, 0.41 g NaH2PO4˙H2O, 0.23 g MgSO4˙7H2O, 5.00 g fructose, 7.50 g lecithin, and 5.00 g mannitol in 968.95 g distilled H2O) combined with 5.0% dimethylsulfoxide and mixed in a 1:4 sperm : medium volume ratio. The highest fertilization percentage obtained with cryopreserved semen was 87.7. No fertilization was obtained when glycerol, ethylene glycol, or propylene glycol were the cryoprotectants. Mean freezing rates faster than 5 C/minute were more effective than slower rates.