Abstract  [Aim]  To determine the effects of delayed mating on the longevity and reproduction of Megabruchidius dorsalis (Fahraeus) (Coleoptera: Bruchinae). [Methods]  Indoor experiments were carried out to investigate the effects of three delayed mating treatments (delayed mating of both sexes, delayed mating of the male only, delayed mating of the female only) on preoviposition period, oviposition period, number of eggs, hatching rate, offspring sex ratio, and adult longevity. [Results]  Simultaneous delayed mating of both sexes, and delayed female mating, significantly increased female M. dorsalis longevity. However, there was no significant effect of any of the delayed mating treatments on male longevity. Of the three delayed mating treatments, delayed mating had adverse effects on M. dorsalis oviposition period, oviposition frequency, number of eggs, and hatching rate. In contrast, there was no significant effect of delayed mating on preoviposition period. Female oviposition was highest after 1-2 days delay in mating and decreased significantly after a delay of 6-7 days. There was a significant decrease in hatching rate with delayed mating of both sexes and by males alone. [Conclusion]  Delayed mating reduces the reproductive potential of M. dorsalis. The findings of this research provide a foundation for further exploration into utilizing pheromone attraction in field-based M. dorsalis control strategies.