The aim of this study was the investigation of effects of the metenolone enanthate (ME) that is used among athletes as doping and muscle amplifier, on hearts of male and female rats that are in puberty using morphometrical methods.A total of 36 rats which were divided into three separate groups (Experiment, ME; vehicle, PO; control, C) each consisting of 6 male and 6 female rats were used. 0.5. mg/kg metenolone enanthate was applied intraperitoneally into experiment subjects 5 times a week over a period of 4 weeks. At the end of experiment, rats were euthanized and their hearts were cut at the level of musculus papillaris after the fixation in formalin. Hearts were taken out and embedded in paraffin wax. Photos were taken at cut surfaces, and thickness, diameters and surface area levels were measured. Left ventriculus mass (LVM) and left ventriculus mass index (LVMI) were calculated.In the study LVM (p<0.005) and LVMI (p<0.05) were found to be significantly higher in the ME group in females whereas left ventricular lumen diameter (LVLD) were found to be significantly lower (p<0.05). Thus left ventricular hypertrophy development was observed. LVM and LVMI were found to be similar in ME and C groups among male rats and the highest level of these data were found in the group. LVM and LVMI were higher among females (p<0.006).In conclusion, it has been shown that the adverse effects of ME on heart were developing starting from puberty and resulting with the enlargement of the heart and left ventricular hypertrophy and especially among females this condition was more evident. It has also been discussed that the continuous use of drugs may further enhance this condition. © 2012 Elsevier GmbH.