Objectives: This research was designed to study the characteristics of heart rate variability in acute dyspepsia patients compared with normal group. Methods: The testing of HRV was carried out at Oriental Medical Center of ${igcirc}{igcirc}$University with the participation of 94 acute dyspepsia patients and 85 control group people. We checked HRV of the 2 groups that were checked on the first visit day and compared HRV index between groups. Results: In the frequency domain analysis, HF, LF, VLF, LF/HF ratio, TP were significantly lower than control group on acute dyspepsia patient group. HF, LF, VLF, LF/HF ratio, TP were not significantly associated with age. Conclusions: According to this study, autonomic nerve system was more decreased on the acute dyspepsia patient group compared with the control group. Though further studies will be needed, the present finding provide us the possibility that stress is a major cause of the acute dyspepsia along with food factor.