Results of a study on mortality response ofMegabalanus tintinnabulumwhen exposed to chlorine and different temperatures are presented. At 1.5 ppm chlorine residuals, 5 mm barnacles showed 100% mortality in 101 h and 30 mm barnacles in 156 h. At relatively high levels of chlorine residuals (15 ppm), all the size groups showed 50% and 100% mortality at identical exposure times. Exposure to a temperature of 35°C showed 100% mortality of the 5 mm size group in 9.9 h and 50% mortality in 3.98 h. All the size groups showed 100% mortality at identical exposure times above 40°C. While chlorination appears to be the method of choice in operating power plants, heat treatment can be considered for use in new plants. The heat treatment method that is reportedly successful in California can be more economical if practised in India. This paper emphasises application of the two methods in power plants and the need for more biological information to control power plant biofouling in Indian waters.