South Asians (SAs) have a greater risk of cardiovascular disease including hypertension, (CVD) than White Europeans (WEs). Whether this reflects disturbances in autonomic control of the cardiovascular system and whether this might be present an early adulthood has not been tested. Thus, we performed studies on young WEs and SAs (10, 8 respectively, aged 19-24; equal numbers of men and women in each group) in which arterial blood pressure (ABP), heart rate (HR), ECG and respiration were recorded at rest, during mental stress (3 min Colour Stroop test) and during 5 min slow breathing (6 breaths/min). Baroreflex sensitivity (BRS) was calculated by the sequence method as change in R-R interval evoked by spontaneous up and down sequences in systolic pressure (SP) at rest and during mental stress and as the relationship between R-R interval and the fall in SP evoked by standing from a squat position before and following mental stress. Heart rate variability (HRV) was computed in the time- and frequency-domains during mental stress and slow breathing. Comparisons within and between WEs and SAs were done by paired and un-paired t-tests respectively. At rest, WEs and SAs had similar mean ABP (mABP, 82.2±2.1 vs 82.0±2.8 mmHg), HR (70.1±3.4 vs 64.5±4.5beats/min) and BRS (up-sequence: 1.1±0.09, down-sequence: 1.2±0.05 vs 1.2±0.04 and 1.3±0.06ms/mmHg). Mental stress evoked similar increases in mABP and HR in WEs and SAs, but was accompanied by less depression of BRS in SAs than WE especially during down-sequences (to 0.69±0.11 vs 1.1±0.07*ms/mmHg, *: P<0.05, WE vs SA). Further, in the time domain, RMSSD and pRR50, indices of vagal activity, were depressed during mental stress in SAs only, whereas following mental stress BRS during squat to stand, an index of cardiac sympathetic activity was depressed in WEs only (0.6±0.04 to 0.3±0.09* vs 0.6±0.09 to 0.5±0.11ms/mmHg). During slow breathing, ABP tended to decrease in both WEs and SAs (P,0.05; P=0.09 respectively), but SDRR increased in SAs only. These results suggest that baroreflex regulation of ABP is disturbed in young adult SAs relative to WEs, with SAs showing more persistent vagally-mediated tachycardia in response to falls in ABP during mental stress than WEs. Moreover, whereas, WEs showed depressed baroreflex sympathetically-mediated tachycardia for several minutes following mental stress, this was not the case in SAs. Such disturbances in SAs may be early markers of future CVD and hypertension in SAs. However, the finding that increased vagal activity in young SAs but not WEs raises the possibility that practice of regular slow breathing may help restore respiratory-cardiovascular interactions in SAs and so help limit CVD.