Abstract: Different bacterial species were isolated from different areas of the Kor River and growth pattern of these bacteria were evaluated. In this study the samples were collected from four stations throughout the Kor River in four seasons. Isolation of mercury resistant bacteria was performed using the primary enrichment method and directly plating on agar containing Hg(II). Growth kinetics of most mercury resistant and sensitive bacteria were studied in LB broth containing 20 mg L-1 HgCl2 per liter. Pseudomonas sp., E. coli, Serratia morcescens, etc. was identified as mercury resistant bacteria. Isolated bacteria from the most mercury polluted stations showed high levels of resistance to this toxicant. Growth curve of mercury resistant bacteria was obtained the same as the standard growth curve of bacteria. Present results showed that enhancement of mercury levels in the environment will increase the levels of resistance to mercury among the bacterial communities residing in this contaminated sites.