BACKGROUND:Epidemiological studies have shown significant ethnic differences in coronary heart disease death rates with South Asians showing significantly greater coronary heart disease mortality than other groups. PURPOSE:This research examined ethnic differences in cardiovascular reactivity (CVR) among Chinese, Malays and Indians in Singapore as well as a sample of Indians living in India. METHODS:Experiment 1 examined differences across 303 Chinese, Malay and Indian undergraduates in Singapore, while Experiment 2 looked at differences in CVR between Indian participants from Singapore, and 145 Indians living in India. Systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), cardiac index (CI) and total peripheral resistance index (TPRI) were measured during baselines and five laboratory tasks. RESULTS:Ethnicity main effects for SBP and CI reactivity were obtained in Experiment 1, with Indians showing significantly lower BP and CI reactivity than the Chinese and Malays. Significant main effects for sex were found with females showing lower reactivity than males for TPRI, and greater reactivity than males for HR and CI. Experiment 2 found that participants from India showed higher reactivity for SBP, HR and CI, while Indian participants from Singapore showed higher TPRI reactivity. These differences, however, often varied by task. CONCLUSIONS:These results point to differences in CVR among ethnic groups in Singapore as well as between Indians living in India and those living in Singapore. These differences may reflect cultural differences and need to be explored further with respect to their relationship to different rates of coronary heart disease among these groups.