In 1985, plasma cholesterol, triglyceride, high-density lipoprotein cholesterol, and plasma apoprotein (apo) B levels were measured in 2,103 men (aged 45 to 76 years) without ischemic heart disease from the Québec city suburbs. Occurrence of a first ischemic event (i.e., angina pectoris, acute myocardial infarction, or coronary-related death) was recorded in 114 men between 1985 and 1990. Men with and without ischemic heart disease were classified as normal or in various dyslipidemic groups according to an established algorithm. Of the 1,989 men who remained free of ischemic events, 50% had a normal lipid profile compared with 32% in men with ischemic heart disease. Although the prevalence of type IIb and IV dyslipidemias was similar in men with and without ischemic heart disease, type IIa (16% vs 10%), hyperapo B-hypertriglyceridemia (12% vs 6%), hyperapo B-normotriglyceridemia (11% vs 7%), and hypoalphalipoproteinemia (18% vs 13%) were more prevalent in men with than without ischemic heart disease. Adjusted odds ratios (ORs) were not increased in type IIb and IV phenotypes, whereas men with type IIa (OR 2.8), with the 2 hyperapo B phenotypes (hyperapo B-normotriglyceridemia, OR 2.7; hyperapo B-hypertriglyceridemia, OR 3.1) or with isolated hypoalphalipoproteinemia (OR 2.2), were at higher risk. The results of this prospective study confirm the importance of both elevated plasma cholesterol and decreased high-density lipoprotein cholesterol levels as risk factors for ischemic heart disease. They also emphasize the high prevalence of an elevated apo B dyslipidemic state in ischemic heart disease.