This study examined the possibility on the dietary value and cryopreservation of the marine microalga, Isochrysis galbana. Four cryoprotectants, dimethyl sulfoxide (DMSO), ethylene glycol (EG), glycerol (Gly) and 1.2-propanedial (PD) were tested at the concentrations of 1.0, 1.5, 2.0, 2.5 and 3.0 M respectively. The highest survival rates were obtained with 1.5 and 2.0 M of four cryoprotectants yielding a survival rate of 80%. Cell concentration of 30 × 104 cell/ml at the initial point of the experiment was increased to 365 × 104 cell/ml in 1.5 M of dimethyl sulfoxide, 298 × 104 cell/ml in 1.5 M of ethylene glycol, 512 × 104 cell/ml in 1.5 M of glycerol, and 385 × 104 cell/ml in 1.5 M of 1.2-propanedial after five days, respectively. In dietary value experiment, survival rate and growth were not significantly different.