Abstract: The isolated pure compound phenyl ethyl β-D glucopyranoside from the stem of the plant Sida rhombifolia was evaluated for larvicidal activity against common filaria vector, Culex quinquefasciatus at different instar under laboratory conditions. The LC values for the isolated compound was 36.22, 43.94 and 50 44.92, 58.34 and 60.40, 63.32 and 70.72, 82.52 ppm for 1st, 2nd, 3rd and 4th instar larvae Culex quinquefasciatus at 24 and 48 h post exposure, respectively.