OBJECTIVE To compare plasma androgen levels in diabetic and nondiabetic men and to determine their relation to diabetic dyslipidemia. METHODS A population-based, case-control study. METHODS Community. METHODS Men 53 to 88 years of age from the Rancho Bernardo, California, cohort who were screened for diabetes using an oral glucose tolerance test. METHODS Plasma androgen levels were compared in 44 men with untreated non-insulin-dependent diabetes mellitus and 88 age-matched men who had a normal glucose tolerance test. The relation of lipid and lipoprotein levels to androgen level and diabetic status was assessed before and after adjusting for covariates. RESULTS Men with diabetes had significantly lower plasma levels of free (4.96 nmol/L compared with 5.58 nmol/L) and total testosterone (14.7 nmol/L compared with 17.4 nmol/L), dihydrotestosterone (428 pg/mL compared with 533 pg/mL), and dehydroepiandrosterone sulfate (DHEA-S) (1.92 mumol/L compared with 2.42 mumol/L) than nondiabetic men. They also had significantly lower high-density lipoprotein (HDL) cholesterol and significantly higher triglyceride levels. Differences were not explained by obesity, alcohol use, or cigarette habit. Overall, the total testosterone level, but not the free testosterone level, was positively correlated with the HDL cholesterol level (P = 0.009) and negatively correlated with the triglyceride level (P = 0.0001). Similar associations were seen in analyses restricted to the men without diabetes. CONCLUSIONS Lower levels of endogenous androgens are seen in older diabetic men, and low androgen levels are associated with diabetic dyslipidemia.