In many animals, males contribute substantially to caring for their young but also have the opportunity to enhance their reproductive success by attracting additional mates or by seeking copulations with females that are already paired to other males. Sometimes, the opportunity to gain these additional matings coincides with periods when males are providing parental care. At such times, males might be expected to allocate time and effort to these alternative behaviours in a way that maximizes their overall reproductive success. But do they? Here, we examine the recent evidence for a tradeoff between parental effort and additional mating effort and highlight some of the factors that might influence how this conflict is resolved. We conclude that, in spite of the paucity of comprehensive studies, this tradeoff has a potentially important and often overlooked influence on parental behaviour in a range of taxa.