Objective: To examine the longitudinal relation between perceived stress in the previous month and perimenstrual symptom severity across two cycles among regularly menstruating, healthy women (n ¼ 259). Methods: At baseline (11 days before the first cycle), participants completed the 4-item Perceived Stress Scale (PSS) for the previous month (first cycle exposure) and questionnaires on lifestyle factors. On cycle day 22 of a standardized 28-day cycle, participants again completed the PSS for the previous week (second cycle exposure) and each week rated the severity (none, mild, moderate, severe) of 17 psychological and physical symptoms (e.g., crying, cramping, pain). Mixed models estimated the association between perceived stress scores and number of moderate=severe symptoms and symptom severity scores, allowing both stress and perimenstrual symptoms to vary by cycle. Results: Adjusting for age, education, passive and active smoking, and waist=height ratio (WHtR), high stress (fourth quartile PSS) was associated with an increased risk of reporting !8 or more (OR 7.2,) and !5 (OR 2.5, 1.6-4.1) symptoms as moderate=severe during the perimenstrual period compared with lower stress (quartiles one, two, and three). Stress scores were positively ( p < 0.0001) associated with increased symptom severity scores for total, psychological, and physical symptoms. Conclusions: These analyses show that higher perceived stress precedes an increased severity of perimenstrual symptoms. Stress reduction programs may be an effective, nonpharmaceutical treatment for physical and psychological symptom relief.