Purpose To compare the prevalence of thyroid disease in patients with retinitis pigmentosa, in patients with gyrate atrophy of the choroid and retina, and in patients with no history of ocular disease. Method Forty-four patients with retinitis pigmentosa, 34 patients with gyrate atrophy, and 30 normal control patients with no ocular disease were evaluated in a case-control study for the presence of thyroid disease. Results Thyroid disease was diagnosed in six of 44 patients with retinitis pigmentosa and seven of 34 patients with gyrate atrophy but in only one of 30 control patients. Compared with control patients, the odds ratio for the occurrence of thyroid disease was 6.2 for patients with retinitis pigmentosa and 12.7 for patients with gyrate atrophy. Conclusion These data suggest an increased occurrence of thyroid disease in patients with retinitis pigmentosa and gyrate atrophy.