Objectives: To identify the difference of autonomic nervous system activity in women with overactive bladder between women with pre-menopausal onset and post-menopausal onset. Methods: Total of 46 women with overactive bladder participated in this study. Patients were categorized in two groups, patients with pre-menopausal onset(n=31) and post-menopausal onset(n=15). We measured and compared parameters of Heart Rate Variability of patients. The results were analysed using SPSS for windows 12.0. Results: On frequency domain analysis, the patients with post-menopausal onset had significantly decreased mean value of Total Power, High Frequence, Low Frequence, compared with the patients with post-menopausal onset. Conclusion: Decreased Total Power of patients with post-menopausal onset indicated that they may have had decreased activity of autonomic nervous system. Also, the patients with pre-menopausal onset had relatively increased sympathetic activity than the patients with post-menopausal onset.