In a 16-year follow-up study (ending in 1998) of 3,686 Danish men and women aged 30-71 years at recruitment, the association between energy intake from dietary fat and the risk of coronary heart disease was evaluated while assessing the possible modifying role of gender and age. In the models used, total energy and protein intake were fixed. Differences in intake of energy from fat thus reflected complementary differences in intake of energy from carbohydrates. A 5% higher level of energy from saturated fat intake was associated with a 36% greater risk of coronary heart disease among women (hazard ratio (HR) = 1.36, 95% confidence interval (CI): 0.98, 1.88). No overall association between saturated fat and coronary heart disease was found among men. However, age-dependent analyses showed that saturated fat was positively associated with coronary heart disease among the younger men (HR = 1.29, 95% CI: 0.87, 1.91) and the younger women (HR = 2.68, 95% CI: 1.40, 5.12) but not among the older men (HR = 0.94, 95% CI: 0.70, 1.28) and the older women (HR = 1.22, 95% CI: 0.86, 1.71). Polyunsaturated fat was inversely associated with coronary heart disease among women and men, although not significantly. In conclusion, the present study suggests that coronary heart disease risk relates to both the quantity and the quality of dietary fats.