A traditional view of multi-male primate groups has held that males provide relatively little direct care to infants, possibly as a result of low confidence of paternity associated with a relatively promiscuous breeding system. In the last five years this view has changed as a result of a careful documentation of intimate male-infant affiliations in certain species, especially the savanna-dwelling baboons (Papio spp.). The occurrence of these affiliations raises the question as to whether males care for their own offspring preferentially and, if so, on what basis male confidence of paternity is mediated. Recent field studies of baboons suggest that male-infant relationships are mediated through affiliations between the males and the infants' mothers, but the degree to which these male-female affiliations are based on prior mating experience (hence, paternity) has not been established. Comparative studies of male-infant relations in primates have given little attention to the variation in the intensity and form of male care patterns within the set of species that have a multi-male social organization. Among multi-male species, male care of young is reported most often in baboons and barbary macaques (Macaca sylvanus) and least often in other macaques, chimpanzees (Pan troglodytes), and vervet monkeys (Cercopithecus). This interspecific variation may result both from differences in the importance of male care to infant survival and from differences in male confidence of paternity, which in turn may relate to seasonal breeding patterns and, in particular, to the presence or absence of conspicuous signs of ovulation in females.