This paper describes the efficiency of chlorination in the seawater cooling system of a power plant located in the Southern coastal area of India. Stainless Steel (SS) and Titanium (Ti) coupons were immersed for a period of 4 x 6 months. Test coupons were collected and wet weight was determined at monthly intervals from intake dyke and pump house regions for biofouling biomass. Species abundance and composition were analysed and the mean value was noted. Low-dose chlorination (0.2 ±0.1 ppm) and shock-dose chlorination for 3 x 20 min/day (0.4 ±0.1 ppm) were given in the pump house region during entire study period. Biofouling biomass at the seawater intake station ranged from 98 to 4767 g/m2 and 102 to 4831g/m2on SS and Ti coupons respectively whereas in the pump house (chlorinated) the settlement was negligible and this proved the efficiency of chlorination in mitigating the biofouling.