Diabetes mellitus is a metabolic disorder affecting various organs of the body. In many patients with diabetic mellitus, typical symptoms associated with the disease manifest only after sufficient cumulative effect of diabetes mellitus. As a result, diabetes related complications and associated clinical conditions may be present by the time it is clinically diagnosed. One of such complications which remain subclinical in diabetes is autonomic neuropathy. Because of its association with a variety of adverse outcomes including cardiovascular deaths, cardiovascular autonomic neuropathy is the clinically most important and well-studied form of diabetic autonomic neuropathy. Heart rate variability of 60 patients with type 2 diabetes mellitus (T2DM) and 30 controls were assessed. Resting electrocardiogram (ECG) at spontaneous respiration was recorded for 5 minutes in supine position. The data are expressed as median (interquartile range). The p value <0.05 was considered statistically significant. All the time domain measures, standard deviations of normal to normal R-R intervals (SDNN) [26 (15.5-35) vs 36 (30-40.25) ms, p=0.002], square root of the mean of the squared R-R intervals (RMSSD) [25.9 (11.95-40.45) vs 36.65 (27.05-44.13) ms, p=0.002], number of R-R intervals that differ by more than 50 ms (NN50) [13.5 (1-70) vs 58 (15.5-86.5) count, p=0.002] and percentage of NN50 (pNN50) [3.5 (0.23-21.83) vs 16.4 (4.45-27.63) % , p=0.002] were significantly lower in T2DM. In frequency domain, low frequency (LF) power [81 (32-148.75) vs 126 (85.25-237.75) ms2, p=0.007], LF power [28.8 (20.78-36.13) vs 36.05 (24.6-43.5) %, p=0.008], high frequency (HF) power [81 (16.75-187.75) vs 182.5 (121.5-281.75) ms2, p=0.001] and HF power [42.15 (27.73-50.65) vs 51.6 (43.58- 62.05) %, p=0.001] were significantly lower in T2DM whereas LF nu [45.25 (35.28-63.93) vs 44.65 (33.7-65.35)] and LF/HF ratio [0.776 (0.543-1.13) vs 0.7005 (0.397-0.999)] were comparable. In Poincare plot, standard deviation (SD)1 [18.5 (8.73-28.98) vs 26.2 (19.33-31.65) ms, p=0.003] and SD2 [37 (26.13-51.18) vs 48.6(39.63-56.15) ms, p=0.002] were lower in T2DM. These data suggest that patients with T2DM have reduced cardiovascular autonomic control especially parasympathetic control.