Although rarely observed, vascular diseases in children constitute a complex clinical problem. Until recently the diagnostic approach to infant vascular diseases was based on invasive methods such as arteriography, but now the use of ultrasonographic methods such as Doppler c.w. and Echo Doppler Color Flow (EDCF) in angiology can offer new and interesting application even in the pediatric age range. In the present study 15 children affected by vascular diseases (eight with arteriovenous fistulas (AVF), two with pseudoaneurysms, and five with angiomas or cysts) either of iatrogenic or congenital etiology, were examined by Doppler c.w. and EDCF. In three additional cases a suspected vascular disease was not confirmed. The data obtained by Doppler c.w. and EDCF proved useful to perform a preoperative diagnosis; however some diagnostic criteria differed from those described in adulthood, as in the AVF cases, for instance, we observed the prevalence of indirect signs such as alterations of venous flow, and the presence of "multicolored speckled mass" and of "the spreading of the color in extravasal space" rather than a direct connection between an artery and a vein. Also pseudoaneurysms were easily detected by EDCF. In two cases of congenital AVF, the diagnosis was confirmed by arteriography. Surgery was performed in 9 children, 7 with AVF and 2 with pseudoaneurysm; in all cases, the vascular defect detected by ultrasonography was visualized and corrected. In 7 cases EDCF was also used in the follow-up. In conclusion this study suggests a possible more extensive use of ultrasonographic methods in the diagnostic approach to vascular diseases in pediatric age groups, and points out their validity in screening very young patients and in their surgical follow-up.