To evaluate the effect of melatonin implants on mounting capacity of the rams in spring, both in group and individually, 6 males received three implants on February (M), while another 6 males remained as control (C). In late March, 60 ewes were synchronized in estrus and divided into 3 groups (n = 20), introducing 4 males in each group (2M+2C). During six hours a sexual test was performed, recording the number of services and mounts, and the interval between services. Four days later, 60 ewes were divided into 12 groups (n = 5), introducing one male in each group to run single tests. Treated males showed a greater sexual activity than control ones (C: 24.5 ± 3.0; M: 25.9 ± 2.3 mounts+services; P < 0.05) and a shorter interval between services (C: 36.6 ± 6.6; M: 27.6 ± 2.1 min; P < 0.05). In group rams were able to mount and serve a greater number of times than individually (Group: 27.8 ± 3.1; Individual: 22.6 ± 1.8; P < 0.05). In conclusion, treatment of rams with melatonin implants in spring resulted in an increased number and frequency of mounting activity. Moreover, a higher sexual activity was observed when rams were in group.