Abstract The concentration of blood testosterone and its correlations with plasma lipids were studied in 23 middle aged survivors of myocardial infarction. They had significantly higher mean cholesterol, triglycerides and total lipids than controls. Plasma triglycerides were highest in five patients who showed the lowest plasma testosterone values. The mean plasma testosterone was significantly lower ( P < 0.001) in the myocardial infarction patients (ovbar|X: 4360.3; S.E.: 584.9pg/ml) than in control group of similar ages ( X : 6880.4; S.E.: 484.9pg/ml). Many of these patients, although fully recovered, seemed to have a reduced testosterone secretion.