Regional cerebral blood flow (rCBF) was investigated with single photon emission computed tomography (SPECT) method using technetium-99m hexamethylpropylene amine oxime (Tc-99m HMPAO) in 23 children and adolescents (10 boys, 13 girls) with major depression diagnosed according to the DSM-IV criteria and 9 healthy volunteers (5 boys, 4 girls). None of the patients was under medication. The SPECT scan was carried oft 10 minutes after the injection of 7.4 MBq (200 MCi) of Tc-99m-HMPAO per kg body weight, acquiring 64 views for 360° at 30 sec per frame on a 64x64 matrix and using a low energy, high-resolution parallel-hole collimator. Coronal, sagittal and transaxial slices that parallel to the orbitomeaal line were generated. All slices were one pixel thick. For the semiquantitative analysis of the data, the ratios of the mean counts/pixel to the whole slice were calculated for 24 regions on thee consequtive transaxial slices in the orbitomeatal plane. Additionally, left/ right and frontal/occipital ratios were also calculated. According to our results, rCBF seems to be decreased in anterofrontal region in the study group. There is no significant difference between right and left regions and the gender mean. The childhood depressoin score had no correlation with blood flow in alt regions although STAIC-trait scores had a negative correlation with blood flow in anterofrontal, left prefrontal, and left temporooccipital regions.