Axenic cultures of symbiotic cyanobacterial isolates Aphanocapsa sp. (NTK28), Nostoc sp. (NTK29 and NTY30) were subjected to different concentrations of heavy metals such as cadmium and lead. The concentration of cadmiumand lead in themediumwas 0.1, 1.0, 10, 100 and 1000 ppm, respectively. The maximum growth rate was observed for the three tested organisms at 0.1 and 1.0 ppm concentrations whereas for the other concentrations no significant growth was observed. In growth concerned with Lead, initially growth could be observed at all the concentrations, but at 15th day growth gradually decreased in Aphanocapsa sp. (NTK28) and Nostoc sp. (NTK29), whereas there was a gradual increase in growth in Nostoc sp. (NTY30).