To investigate the need for hormonal treatment in patients with functional ovarian cysts after induction of ovulation, a randomized prospective study was performed. Fifty-four patients who were found to have ovarian cysts after induction of ovulation were randomly assigned to two groups: a) Treatment with estrogen/progesterone. b) Expectant management. The main outcome measure was resolution of ovarian cysts. There was no significant difference between the groups. We conclude that hormonal treatment is not necessary in cases with functional ovarian cysts after induction of ovulation.