The toxicity of materials derived from seed of Pongamia pinnata Pierre toward to third instar larvae of Aedes aegypti and Culex pipiens pallens was examined using direct contact bioassay. Results were compared with those of the currently used insecticides: fenthion and temephos. The active principles of Pongamia pinnata were identified as the karanjin (1), pongamone (2), palmitic acid (3) and karanjachromene (4), by spectroscopic analysis. Based on 24h LC50 values, karanjin (14.61 and 16.13 ppm) was the most toxic compound but less effective than fenthion (0.0031 and 0.068 ppm) and temephos (0.016 and 0.056 ppm) against Ae. aegypti and Cx p. pallens. Moderate toxicity was produced by pongamone (34.50 and 39.53 ppm), palmitic acid (36.93 and 42.96 ppm), and karanjachromene (43.05 and 48.95 ppm). P. pinnata seed derived materials, particularly karanjin, merit further study as potential mosquito larvicides for the control of mosquito populations in light of global efforts to reduce the level of highly toxic synthetic larvicides in the aquatic environment