The Pacific oyster Crassostrea gigas oocytes were exposed to 4 cryoprotectants, dimethyl sulfoxide (DMSO), ethylene glycol (EG), methanol, or polyethylene glycol (PEG), each with 4 four concentrations (5, 10, 15, and 20%) and for 10, 20, 30 or 40 minutes for permeation. The oocytes were then fertilized, using normal sperm of the species. Fertilization and hatching rates were clearly influenced by cryoprotectant species and their concentration and permeation time. Overall, they decreased as concentrations and permeation time of cryoprotectants increased with optimum results at concentrations of 5-10% and a permeation time of 10 minutes. Larval abnormalities, a sign of the chemical damage, were a representative phenotype which was higher at a higher concentration and longer duration of the chemicals. In conclusion, best result was from 5% DMSO exposure for 10-20 minute  permeation.