The authors present six cases of subarachnoid hemorrhage secondary to rupture of an aneurysm of the pericallosal artery. Four of these were of the berry type and were located at the genu of the corpus callosum; in two instances the aneurysm was found at the bifurcation of an azygous or a bihemispheric pericallosal artery respectively. A fifth lesion was of the fusiform type and the sixth one represented most probably a false aneurysm. All patients have been operated upon, but in three only clipping of the neck was feasable. In the remainder one pericallosal or the azygos artery was occluded intentionally. Postoperatively, severe mental perturbation, incontinence and seizures were encountered, but all symptoms cleared during the follow-up period, and subarachnoid hemorrhage never recurred.