In modern zoos, training should be an integral component of the animal care and management. The benefits of training include the opportunity for positive interactions with caretakers. This study was carried out with a group of vervet monkeys (Chlorocebus aethiops) housed at the Garda Zoological Park, Italy. Using focal animal sampling, we observed the behaviour performed by all group members from December 2007 to August 2008. The group took part in a training programme to be isolated in a familiar area before the subjects were included in a cognitive study. We collected behavioural data during a pre-training period to assess the social behaviour of the colony and during the training period to investigate the effects of the training programme on the behaviour of individuals. Additionally, a second phase of the study was conducted and training sessions with individual monkeys were video-recorded to determine the behaviour of animals during each training session and to thus confirm that they were suitable for participating in the procedure. Our results suggest that the training programme enriched the daily routine of these captive primates by increasing affiliative behaviours while decreasing agonistic behaviours. Furthermore, there was behavioural response variability among the individuals under the training procedure. However, all the individuals were trained to calmly enter a familiar area and be isolated from other members of the group. In conclusion, our findings highlight the importance of using positive reinforcement training to reduce the tension directly associated with potentially stressful procedures by allowing primates to participate voluntarily in these procedures. In addition, the training was found to be an enrichment tool for vervet monkeys.