The National Cholesterol Education Program treatment guidelines define a plasma total cholesterol of less than 200 mg/dl as "desirable" and recommend no further evaluation of plasma lipid or lipoprotein levels in patients with coronary artery disease (CAD). To determine the prevalence of dyslipidemias in the presence of coexistent CAD and total cholesterol less than or equal to 200 mg/dl, a retrospective case-control study of 1,000 patients who underwent diagnostic coronary angiography was performed. Of 351 patients with total cholesterol less than or equal to 200 mg/dl, 76% of the men (244) and 44% of the women (107) had angiographically demonstrated CAD. In men with CAD and total cholesterol less than or equal to 200 mg/dl, there was a significantly greater prevalence of low levels of high density lipoprotein (HDL) cholesterol (less than or equal to 35 mg/dl), age greater than 50 years, systemic hypertension and diabetes mellitus compared to non-CAD control subjects. In women with CAD and total cholesterol less than or equal to 200 mg/dl, HDL cholesterol less than or equal to 45 mg/dl and diabetes mellitus were also significantly prevalent. Multiple logistic regression analyses revealed that HDL cholesterol, hypertension and age in men and very low density lipoprotein cholesterol in women were significantly associated with CAD after adjustment for other risk factors. These results suggest that a complete lipid and lipoprotein analysis be obtained in all patients with CAD, irrespective of the plasma (or serum) total cholesterol level.