Childhood growth hormone deficiency (GHD) decreases left-ventricular (LV) mass, but impairment of cardiac function has never been documented. The objective of this study was to assess the cardiac effects of GHD and recombinant human growth hormone (rhGH) treatment using conventional echocardiography and tissue Doppler imaging. Complete two-dimensional, M-mode, pulse-wave Doppler echocardiography and pulse-wave tissue Doppler imaging were performed in 12 children (6 male and 6 female patients) with GHD at baseline and at 5.86 ± 1.61 months after rhGH therapy. Recombinant human growth hormone treatment was associated with a significant increase in LV mass index (63.8 ± 27.1 to 79.3 ± 30.3 g/m²; P < 0.01) and LV internal dimensions (21.4 ± 2.63 to 24.0 ± 4.13 mm in systole [P = 0.03] and 36.5 ± 3.90 to 39.5 ± 4.94 mm in diastole [P < 0.01]). There were statistical differences of parameters, such as deceleration time of early peak velocity of mitral, isovolumic relaxation time, and myocardial performance index (103 ± 15.4 to 139 ± 21.2 ms [P < 0.01], 55.5 ± 9.24 to 69.2 ± 3.74 ms [P < 0.01], and 37.8 ± 4.46 to 44.9 ± 5.44% [P < 0.01], respectively). Before and during rhGH therapy, there were no significant differences in fractional shortening of the left ventricle, peak mitral, and tricuspid wave velocities with ratios determined using conventional echocardiography and tissue Doppler imaging. In children, GHD affects heart morphology by inducing a decrease in cardiac size, but it does not modify cardiac function. Recombinant human growth hormone treatment increases cardiac mass, deceleration time of early peak velocity of the mitral valve, isovolumic relaxation time, and myocardial performance index, but it does not make a difference in other parameters of conventional echocardiography and tissue Doppler imaging.