We experimentally tested if differences in the mating history of old males affects their offsprings’ performance in the mosquitofish, Gambusia holbrooki. Upon maturation, males were housed for the duration of a natural field breeding season (23 weeks) either with mating access to females (‘lifetime mating’) or with visual but no physical access to females (‘no mating’). We then paired these males with a female to test whether male mating history had a significant effect on their mate’s breeding success or offspring performance. The daughters, but not the sons, of ‘no mating’ treatment males matured significantly sooner, and at a significantly smaller size, than those of ‘lifetime mating’ treatment males. There was, however, no effect of male mating history on their daughters’ initial fecundity, or on proxy measures of their sons’ reproductive success. These results, when combined with earlier studies showing effects of male mating history on sperm quality, growth and immunity, suggest that variation in paternal effects currently attributed to male age could partly arise simply because older males have usually mated more often than younger males.