Insecticidal activity of Melia azedarach methanol extract and nucleopolyhedrovirus (SLNPV) against Spodoptera littoralis larvae was evaluated under laboratory conditions. NPVs showed high significant toxicity on the 2nd and 4th instars larvae; while, the Melia extract was a relatively high toxic against the 2nd instar larvae and less effective against the 4th instar. The extract recorded strong reduction in larval weight as compared to the control. Generally, Melia extract potentiates the effect of SLNPV by producing mortality within a short time and negatively influences the larval growth and development which could result lesser feeding damage to the host plant.