Hand-reared cercopithecids may develop inappropriate behaviours and have lower breeding rates. Generally, hand-rearing cercopithecids is not advisable, but when a species in this family is threatened in the wild and its breeding rate in captivity is not enough to ensure a self-sustaining population, hand-rearing could be helpful. In such cases, to proceed with an early integration of the hand-reared infant to its social group is advisable in order to allow the infant to grow up with the chance of observing and developing species-specific and social behaviours, and avoiding the appearance of inappropriate behaviours. Three cercopithecids from two species, Cherry-crowned mangabey Cercocebus torquatus torquatus and Drill Mandrillus leucophaeus, were introduced to their respective family groups after a short period of hand-rearing, when still being considered as infants. The procedures and results are given in this paper.