This was a prospective, cohort study in Korean pregnant and postpartum women, to estimate the prevalence and patterns of sleep disturbances. The survey was composed of the following validated sleep questionnaires: the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Women's Health Initiative Insomnia Rating Scale, Berlin Questionnaire for sleep disordered breathing, the international restless leg syndrome (IRLS) Study Group criteria, and the Johns Hopkins Telephone Diagnostic Interview Form (JHTDIF) for RLS. Statistical analyses were performed using SPSS version 18.0. Six hundred eighty-nine women completed sleep surveys. The overall percentage of women with very poor sleep quality (a PSQI score greater than 10), clinically significant insomnia (a total score of 9 or more), excessive daytime sleepiness (a total ESS score of 10 or more), short sleep duration (less than 7 hours per night) were 80.7%, 50.5%, 34.0% and 29.5%, respectively, and all of three parameters became increased as pregnancy progressed and after delivery ( p = 0.002, 0.001, and 0.001, respectively). The overall positive rates in Berlin and RLS questionnaires were 25.4% and 19.4%. In conclusion, sleep disturbances are prevalent among Korean pregnant and postpartum women, and increase significantly as pregnancy progresses and after delivery.