On the basis of 146 angiographic studies performed by retrograde brachial injection in patients aged 10 days – 10 years, this study analyzes normal arterial and venous pattern of the vertebro-basilar system in infancy and childhood (50 cases); and the pathological findings from infratentorial tumors (40 cases). Diagnostic accuracy was 95 %, the arterial phase having been longer the more diagnostic because of the intra-axial nature of all investigated tumors; the remaining 5 % of false negative studies included only cases of brain stem tumor. Some findings useful in diagnosis of the nature of the tumors have been considered. These results and the lack of complications suggest this simple examination as the first technical aid (at least with respect to time) in the preoperative study of children suspected of a tumor in the posterior fossa. The exception is constituted by brain-stem tumors, which confirm air study by lumbar route as the procedure of choice.