The presence of heavy metals in water and wastewate r is increasing due to the industrial development-d isposal in the sewerage or in the water bodies. Cadmium, mercu ry and lead are the big three heavy metals posing t he greatest hazard to human health, in addition to As, Be and C r which are known to be carcinogenic. Laboratory in vestigation was conducted to study the extent and efficiency of cadmium accumulation in Chlorococcum humicolum and Phormidium foveolarum. The accumulation of cadmium increase with increasing concentration of metals in the medium. The mutants tolerant to high level of cadm ium metals were obtained by repeated sub culturing. Tolerance of Chlorococcum humicolum to cadmium 2mgl -1 to 12mgl -1 and Phormidium foveolarum 2 to 10 mgl -1 . Morphological changes were recorded in both Chloroc occum humicolum and P. foveolarum at higher level o f cadmium