The severity of premenstrual syndrome symptoms has been described by different investigators as varying directly or inversely with the severity of dysmenorrhea. In a large population of women undergoing comprehensive psychological and medical evaluation for premenstrual syndrome complaints, the authors examined the relationship between menstrual cycle parameters and premenstrual syndrome. The severity of premenstrual symptoms varied directly with the severity of dysmenorrhea and premenstrual spotting but was not associated with any other menstrual cycle parameter. Multivariate analysis revealed that social and psychological variables are more strongly associated with variations in premenstrual symptoms than are any menstrual cycle parameters.