Mosquito borne diseases are detrimental to human health; thus, researchers are constantly conducting studies on how to reduce the number of mosquito borne pathogen. The study was conducted to verify the larvicidal effect of rambutan (Nepheliumlappaceum L.) leaf extract against larvae of household mosquito. Qualitative screening of tannin and saponin was done by phytochemical testing. Ethanol extraction and rotary evaporation were performed to obtain the extract. An experimental set-up/larvicidal assay was conducted to determine the effectiveness of the extract as larvicidal agent. The approximate effective concentration of rambutan leaf extract against mosquito larvae obtained from the study was 0.005 showing a death of 84%. To measure the standard toxicity of Rambutan leaf extract against mosquito larvae, the LC90 was computed using the probit y analysis. In this test, the toxicity of the experimental plant extract was computed allowing 90% death of the test larva population. The bioassay analyses of rambutan leaf extract as larvicidal agent has mean death percentage of 91.33.The study concluded that the ethanolic leaf extract of rambutan can be used as a mean of terminating the growth and development of the larvae of household mosquito and control the increase of population of this biological vector.