OBJECTIVE: Adenomyosis, a common gynecologic disease, can cause infertility. Uterine peristalsis (UP) is a wave-like contraction. Abnormal UP has been linked to infertility. The aim of this study using magnetic resonance imaging (MRI) was to compare UP between uterine walls with adenomyosis and normal walls to ascertain the possible effects of adenomyosis on UP. METHODS: Using cine MRI, UP of 139 adenomyosis patients were evaluated. The uterine walls were divided into those with and without lesions. One radiologist evaluated the presence of UP depending on the menstrual cycle phase. In cases where peristalsis was present, the peristaltic frequency and direction were evaluated. For uterine walls with adenomyosis, characteristic movement of peristalsis was evaluated, including low signal conduction, change of endometrial configuration, and irregular signal change. Peristalsis was evaluated further between focal and diffuse adenomyosis. RESULTS: UP was observed significantly more in adenomyosis lesions (113/182) than in normal myometrium (47/96), especially in the luteal phase, but the frequency was not significantly different (6.9 vs. 7.3). Comparison between diffuse adenomyosis and focal adenomyosis revealed that the presence of peristalsis was not significantly different in any cycle phase. Peristaltic direction was observed as cervix-to-fundus in the proliferative and luteal phase. Almost half of the cases showed low signal conduction (48%-59%), change of endometrial configuration (31%-53%), and irregular signal change (41%-56%) in adenomyosis lesions. CONCLUSION: UP in adenomyosis showed a tendency of hyperperistalsis in the luteal phase. It accompanies characteristic peristaltic movement in adenomyosis in about half of patients.