Metabolic risk markers for coronary heart disease (CHD) were determined in apparently healthy females of differing racial origins residing in the United Kingdom. The females were of black (n=122), Oriental (n=144), South Asian (n=128), and white (n=271) origin, premenopausal, non-obese, and aged 16-45 years. In comparison to whites, South Asians had lower serum high-density lipoprotein (HDL) cholesterol and HDL2 cholesterol and higher fasting and oral glucose tolerance test plasma insulin responses. Black females had higher fasting plasma and oral glucose tolerance test insulin and lower serum triglyceride and glucose compared with white females. Orientals differed from whites in having higher fasting and oral glucose tolerance test insulin concentrations. Resting systolic or diastolic blood pressures, total serum cholesterol, HDL3 cholesterol, and low-density lipoprotein (LDL) cholesterol did not differ between groups. Whereas previous studies have demonstrated similar differences in representative samples from different ethnic communities, our results clearly demonstrate that differences also exist in young healthy females, individuals considered to have the least risk of CHD.