Sleep disordered breathing [snoring and obstructive sleep apnea-hypopnea syndrome (OSAHS)] is common in the US and has been associated with negative health outcomes. There has been no long-term prospective study on the association between sleep disordered breathing and psoriasis risk. We prospectively evaluated the association between OSAHS and snoring and incident psoriasis and psoriatic arthritis (PsA) in 71,598 women over an 11-year period (1997-2008) in the Nurses' Health Study. Participants received follow-up questionnaires every 2 years and were asked about snoring, diagnosis of OSAHS, and diagnosis of psoriasis and PsA. We studied individuals who reported data on snoring and OSAHS prior to the diagnosis of psoriasis or PsA. We used Cox proportional hazards to calculate age-adjusted and multivariate risk ratios. Over the follow-up period, there were 524 cases of psoriasis. Women with OSAHS were more likely to have a higher BMI, be hypertensive, have cardiovascular disease, and have type 2 diabetes (p < 0.001 for all). The age-adjusted relative risk (RR) of psoriasis among women with OSAHS was 2.19 (95% CI 1.39-3.45), the multivariate RR was 1.93 (95% CI 1.21-3.08). Further adjusting for night shift work, hypertension, cardiovascular disease, and type 2 diabetes, the multivariate RR was 1.91 (95% CI 1.20-3.05). There was no effect modification by BMI (p = 0.52), hypertension (p = 0.34), or snoring (p = 0.91). OSAHS was not associated with an increased risk of PsA. Although women with OSAHS were more likely to be snorers, we did not find a statistically significant relationship between snoring and the risk of confirmed psoriasis. In this study, we found that women with OSAHS had a significantly increased risk of psoriasis.