The purpose of this study is to evaluate physiological and psychological effects of sanitary napkins on sleep during menstrual periods. Two types of sanitary napkins, the ultra slim type (US) and the thick type (T) were used by 17 women during their menstrual periods. The indexes were a 5-point scale for preferences of the samples, the Oguri-Shirakawa-Azumi sleep inventory MA version (OSA-MA), the ratio of low frequency/high frequency (LF/HF) and the movements during sleep. Most of the subjects selected US as the more comfortable sanitary napkin. In the OSA-MA, the scores of “sleepiness on rising” and “refreshing” for US were higher than those for T. The values of LF/HF were lower when US was used during the 1st and 2nd sleep cycles. Considering these results, the comfortable US did not disturb the natural sleep cycles physiologically, brought deeper sleep early in the sleep period, and caused psychological differences, less sleepiness on rising and feeling more refreshed. Therefore we concluded that comfortable sanitary napkins bring better sleep physiologically and psychologically.