Melanocytic nevi are commonly believed to undergo changes during pregnancy. This is probably related to hormonal influences; however, few studies have been able to prove it. We observed a case of a benign melanocytic nevus, which showed significant enlargement during pregnancy and immediate postpartum regression associated with increased apoptosis of nevus cells. Estrogen and progesterone receptors were not found in our case, although the clinical course still suggested a close association with hormonal influences.