For evaluating the effects of Novaluron on the adult performance of Spodoptera littoralis females, a concentration range of 1.00-0.0001ppm was applied on the newly molted penultimate (5th) instar larvae and a concentration range of 0.10-0.0001ppm was applied on the newly molted last instar larvae. Novaluron failed to affect the adult survival except at the higher concentration levels, regardless the time of treatment. Treatment of last instar larvae resulted in some features of impaired morphogenesis only at the higher two concentrations. On the contrary, no adult deformities had been produced after treatment of penultimate instar larvae. The total adult longevity was significantly shortened, regardless the time of larval treatment. Treatment of penultimate instar larvae with Novaluron resulted in remarkably accelerated the ovarian maturation, at all concentrations except the highest one. On the other hand, a diverse effect was detected after treatment of last instar larvae because Novaluron prohibited this vital process at the higher two concentrations, but remarkably enhanced it at the lower two concentrations. Novaluron exhibited a prevalent stimulatory effect on the reproductive life-time (oviposition period) of adult females to quickly lay eggs during a very short interval, regardless the time of larval treatment.