The authors assessed the relation of hormonal and pregnancy-related factors to the incidence of sarcoidosis in the Black Women's Health Study. On biennial questionnaires, participants (US black women aged 21-69 years at baseline) reported data on diagnoses of sarcoidosis, reproductive history, and medication use. Cox regression models, adjusted for age, education, geographic region, smoking, and body mass index, were used to estimate incidence rate ratios and 95% confidence intervals. During 694,818 person-years of follow-up from 1995 through 2009, 452 incident cases of sarcoidosis were identified. The incidence of sarcoidosis decreased as age at menopause increased (P-trend = 0.03). Both later age at first full-term birth and having a more recent birth were associated with a reduced incidence of sarcoidosis. In models that included both factors, the incidence rate ratios were 0.60 (95% confidence interval: 0.37, 0.97) for age at first birth ≥30 years versus <20 years (P-trend = 0.05) and 0.73 (95% confidence interval: 0.43, 1.24) for <5 years since last birth versus ≥15 years (P-trend = 0.15). No significant associations were observed with age at menarche, parity, lactation, oral contraceptive use, or female hormone use. These results suggest that later full-term pregnancy and longer exposure to endogenous female hormones may be related to a reduced risk of sarcoidosis.