This study was conducted to determine if there is a significant increase in prevalence of hypothyroidism in women with OSAS such that screening might be warranted. Women undergoing polysomnography (PSG) at Duke University between January 1, 2000 and August 21, 2001 were considered for enrollment. Those with a respiratory disturbance index (RDI) >/= 10 were included for further analysis. Demographic data and documentation of thyroid testing was obtained. Thyroid testing obtained within 1 year of the PSG was used for this study. Demographic data of the euthyroid and hypothyroid groups were compared. Prevalence of hypothyroidism was calculated and compared with the prevalence of hypothyroidism in the Framingham study. A total of 118 women had OSAS per PSG. Seventy-five patients had thyroid function testing within 1 year of PSG evaluation. The mean age, body mass index, and RDI in the euthyroid and hypothyroid groups were not significantly different. The prevalence of hypothyroidism was 9.3%; the established prevalence of hypothyroidism in women in the general population is 5.9%. There was no statistically significant difference in the prevalence between these groups. The prevalence of hypothyroidism in women with OSAS is no higher than that seen in the general population. Screening women with symptoms of OSAS for hypothyroidism is unlikely to be useful.