Our objective for this study was to examine symptom severity among women suffering from premenstrual syndrome as well as associations between symptom severity and impairment. In a one-cycle prospective study, various premenstrual symptoms of 91 women were assessed. Tension and irritability were the most severe symptoms. Headache, irritability, self-deprecating thoughts, and depressed mood were the symptoms that were subjectively rated as the most burdensome. Significant correlations were found between the mean premenstrual severity and functional impairment. The severity of premenstrual affective symptoms was related to social impairment. The severity of psychological symptoms was correlated with occupational impairment. These findings confirm the prominent role of premenstrual affective symptoms and support classification guidelines focusing on both affective and physical changes.