Purpose: Oligomenorrhea is clinically important because it can be progressed to amenorrhea. The purpose of this study is to analyse Autonomic Nerve Function of some oligomenorrheic patients by using HRV(Heart Rate Variability). Methods: We studied 35 patients visiting OO Oriental Hospital from 1st November 2006 to 31th May 2007. One woman who takes antidepressant is excluded. 17 oligomenorrheic group and 17 normal menstrual cycle group were compared with HRV. The SPSS 12.0 for windows was used to analyze the data and Mann Whitney U-test were used to verify the results. Results: Mean PR, LF norm, LF/HF ratio of oligimenorrheic group are higher than normal menstrual cycle group. But there is no statistically significance. SDNN, RMS-SD, ln TP, ln VLF, ln LF, ln HF, HF norm of oligimenorrheic group are lower than normal menstrual cycle group. But there is no statistically significance. Conclusion: It can be suggested that oligomenorrhea can be related to increased activities of sympathetic nerve and decreased activities of general autonomic nerve function. But, we need study with more subjects for settling this.