Laboratory bioassay was conducted on the 2nd and 4th instar larvae of Aedes aegypti (Diptera:Culicidae) to investigate the efficacy of Moringa oleifera seed oil (MOSO) and Annona muricata seed oil (AMSO) (200, 100, 50, 25, 12.5 and 6.25 µL/mL) along with a control. Inhibition of emergence (IE) and larval mortality were monitored at 3-hours intervals for a period of 24 hrs. Results showed that MOSO at the highest concentration caused 94% and 70% mortality for both 2nd and 4th instar larvae respectively while AMSO gave 100% for both 2nd and 4th instar larvae. The level of IE was 100% for both toxicants after post-exposure culture for 10 days. Nevertheless, the 2nd instar larvae were more susceptible than the 4th instar. The LD50 values against the 2nd and 4th instar larvae were 18.19 µL/mL and 54.50 µL/mL for MOSO while AMSO were 9.49 µL/mL and 16.11 µL/mL respectively. AMSO was found to be more effective about twice at all stages than MOSO, therefore both oils show promise as biopesticides against Ae. aegypti mosquito larvae although

further evaluations need to be carried out especially on the other mosquito genera and species.