Comparisons of numbers of eggs laid and longevity of singly and multiply mated females of the cabbage looper, Trichoplusia ni (Hübner), revealed a positive relationship between the number of spermatophores received by a female and her oviposition rate in eggs laid per day and her fecundity. Comparisons of numbers of eggs laid and longevity of females either once-mated to virgin males or once-mated to previously mated males revealed no relationship between male mating history and female oviposition rate, female lifetime fecundity, or female longevity, indicating that multiple mating by males does not result in a decline in the quality of their contributions to females during mating. The possible benefits derived by females from multiple mating are discussed.