East Kolkata Wetlands is a conserved wetland utilizing sewage and garbage, generated by Kolkata Municipal Corporation area for cultivation purpose. Cyanobacteria are the photosynthetic prokaryotes having bioremedial capacity. We have isolated a cyanobacterium from the sewage recycling fish-pond of East Kolkata Wetlands. Partial sequence of 16S rDNA gene of the isolated strain showed 100% similarity with that of genus Synechocystis. Isolated strain and Synechocystis sp. PCC6803 survived up to 300 μg ml-1 Pb 2+ and growth was completely inhibited at 400 μg ml-1 Pb2+. All experiments were carried out with 100 μg ml-1 Pb2+ in which growth was the maximum. 91.67% of the total Pb 2+ got adsorbed to the outer surface of the cell and 1% of the total Pb2+ entered the cell of the isolated strain as estimated by atomic absorption spectrometry, but in Synechocystis sp. PCC6803 72.72% adsorbed and 0.96% penetrated. Intracellular and periplasmic depositions of Pb2+ were observed in both the strain. A filamentous structure developed outside the cell wall of the isolated cyanobacterium, but very little change was observed in Synechocystis sp. PCC6803. ZiaR-SmtB like regulator gene was expressed in both the strains after Pb2+ induction. The cDNA sequence of ZiaR of the isolated cyanobacterium shows 100% homology with that of Synechocystis sp. PCC6803. Upon Pb2+ induction, expression of SOD gene increased. cDNA sequence of the SOD gene from the isolated strain showed 98% homology with that of Synechocystis sp. PCC6803. Enzymatic activity of catalase and SOD was also increased. No DNA damage was monitored upon induction with Pb2+. © 2008 Springer Science+Business Media, LLC.