In a case-control study, we compared 238 women with intraocular malignant melanoma to 223 matched controls with detached retinas to evaluate the influence of hormonal factors on the risk of this cancer. We observed increased risk among women who had ever been pregnant (relative risk, 1.4; 95% confidence interval, 0.8, 2.2) and women who used replacement estrogens (relative risk, 2.0; 95% confidence interval, 1.2, 3.1), decreased risk among women who had undergone oophorectomy (relative risk, 0.6; 95% confidence interval, 0.4, 1.0), and no change in risk among women who had used oral contraceptives. Compared to hormonal effects on risk of reproductive tumors, these effects were weaker and less consistent, suggesting that hormonal factors may play only a limited role in causing melanomas of the eye.