Introduction: Aromatase inhibitors (AIs) are increasingly used in children and adolescents to augment adult height. The aim of this study was to investigate the effects AIs have on cardiac morphology, functions and their relation to several metabolic parameters in adolescent boys. Methods: Three groups matched for sex (boys, n = 67), age (median age 13.5 years), weight, height, body mass index, and puberty stages were enrolled: (i) Group 1: 23 patients using AIs (only AI (n = 6) or in combination with growth hormone (GH) (n = 17)) for at least 6 months; (ii) Group 2: 22 patients using only GH, and (iii) Group 3: 22 healthy boys. Two-dimensional, M-mode conventional Doppler and tissue Doppler examinations of the left ventricle (LV) were performed. Bioelectrical bioimpedance analyses was conducted and follicle-stimulating hormone, luteinizing hormone, total testosterone, lipid, and hemogram parameters were obtained. Results: Patients in Group 1 had significantly higher serum total testosterone (p < 0.001) and hemoglobin (p < 0.001) levels, fat free mass (p = 0.005), LV mass (LVM) (p = 0.002), as well as increased LV posterior wall diameter (LVPWD) (p = 0.002), interventricular septum diameter (IVSD) (p = 0.019), and myocardial systolic wave velocity (Sm) (p = 0.020) compared to the two other control groups. No significant differences were observed in terms of diastolic and systolic functions and lipid profiles (p > 0.05). There were positive correlations between total testosterone, hemoglobin levels, LVM, LVPWD and IVSD (p < 0.05). Conclusion: Increased LVM, LVPWD, IVSD and Sm of patients receiving AI therapy in comparison to the control groups, and the significant correlations of these parameters with total testosterone and hemoglobin levels were determined as potential side effects of AIs. These findings emphasize the need of routine cardiac follow-up in patients using AIs.