A study of coronary heart disease and risk factors was conducted in a total Sri Lankan aboriginal population who face imminent extinction due to developmental programmes in the vicinity of their jungle homelands. Coronary heart disease was not detected among the aborigines. Hypertension was present in 5.7% of males and 1.9% of females. 39% of males smoked. Serum cholesterol, triglyceride and high density lipoprotein cholesterol levels were 5.25 mmol/l (SD 0.45), 1.99 mmol/l (SD 0.92) and 1.2 mmol/l (SD 0.2) respectively. Obesity was not seen and the level of physical activity was high. The rarity of coronary heart disease could be attributed to this favourable coronary risk profile.