Cryopreservation of micro-algae is of importance in storage of stock-culture as well as for using as aquaculture feed at any occasions. Three commercially important strains of microalgae, Chaetoceros calcitrans, Tetraselmis gracilis and Chlorella marina were cryopreserved with different levels of post-thaw viability. More than 25% post-thaw viability was recorded for T.gracilis, while C. marina showed>32% post-thaw viability and C.calcitrans up to 20% only. Glycerol and dimethyl sulfoxide (DMSO) were used as cryoprotectants at 5% and 10% (v/v) concentrations.