The effects of anabolic androgenic steroids (AASs) on left ventricular (LV) diastolic function in strength-trained athletes are controversial. The main objective of this study was to evaluate the effects of regular AAS administration in bodybuilders using pulsed tissue Doppler imaging (TDI) to evaluate LV relaxation properties. Fifteen male bodybuilders with a history of intensive, long-term strength training and 16 age-matched sedentary controls were recruited. Six of the bodybuilders reported regular use of AASs, and 9 were drug free. To assess LV diastolic function, each subject underwent standard Doppler echocardiography and pulsed TDI. Drug-using bodybuilders exhibited altered LV diastolic filling characterized by a smaller contribution of passive filling to LV filling compared with their drug-free counterparts. TDI measurements indicated that drug-using bodybuilders had smaller peak E(m) than drug-free bodybuilders and sedentary controls, except at the level of the anterior wall, at which peak E(m) was significantly smaller than in drug-free bodybuilders only. The E/E(m) ratio, an index of LV filling pressures, was not affected by strength training or by AAS use. Drug-using bodybuilders exhibited larger LV end-diastolic diameters, volumes, and masses than their drug-free counterparts. However, no difference was found in LV wall thickness between the groups. In conclusion, drug-using bodybuilders showed a decrease in the contribution in LV passive filling to LV filling associated with a decrease in LV relaxation properties. Because no wall thickening was obtained in drug-using bodybuilders, the decrease in LV relaxation properties might have been be due to an alteration in the active properties of the myocardium, but that has yet to be confirmed.