Reproductive events have a significant impact on women's lives. The aim of this study was to analyze the effects of age at menarche and current menstrual irregularity on psychological well-being and psychopathology. Data were collected in the context of the Finnish population-based Health 2000 study with self-administered questionnaires, a home interview, and a clinical health examination. The Beck Depression Inventory (BDI-21), the General Health Questionnaire-12 (GHQ-12), and the Composite International Diagnostic Interview (M-CIDI) were used to assess psychopathology. The relationships between age at menarche and current menstrual flow irregularity vs. BDI-21 and GHQ-12 scores and M-CIDI diagnoses were studied among 4,391 women aged 30 years and over. Negative, nonsignificant associations were found between age at menarche and BDI-21 and GHQ-12 scores. Young age at menarche was associated with increased risks of any recent mental disorder (OR = 0.894, p < 0.01), major depressive episode (OR = 0.900, p < 0.05), major depressive disorder (OR = 0.888; p < 0.05), and anxiety disorder (OR = 0.892; p < 0.05). Menstrual irregularity was associated with BDI-21 (p < 0.001) and GHQ-12 (p < 0.05) scores, but not with any recent psychiatric diagnosis. Age at menarche and menstrual irregularity have an influence on mental health, particularly on mood and anxiety symptoms. Reproductive features (age at menarche and menstrual irregularity) should be paid attention to during psychiatric evaluations.