A total of 5,000 ethanolic and methanolic extracts of different plant species from 23 nations including Costa Rica, Vietnam, Philippines, India, South Africa, Pakistan and Peru were evaluated for their larvicidal activities against Aedes aegypti, the major vector of dangue, dangue hemorhagic fever and yellow fever. The larval mortalities were observed 24h after treating the larvae to the extracts. At 500 ppm, 179 extracts showed >80% larval mortality in the 24h exposure. Among the extracts tested, the highest larval mortality was observed in the extracts of Piper guianense, Piper nigrum, Piper mocropodum, Piper sem-immersum, Piper magen and Piper pubicatulum. The LC50 value of extract P. guianense, P. nigrum, P. mocropodum, P. sem-immersum, P. magen and P. pubicatulum were 8.84, 11.48, 8.84, 13.86, 9.48 and 10.12 ppm against Ae. aegypti. It is suggested that P. guianense, P. nigrum, P. mocropodum, P. sem-immersum, P. magen and P. pubicatulum can be developed as potent larvicidal agents against Ae. aegypti.