&NA;A 30‐year‐old woman underwent surgical partial callosotomy (posterior half) for removal of an arteriovenous malformation. The patient submitted to neuropsychological evaluation before and after surgery for a period of 8 months. There was transient dysfunction attributable to disconnection of parietal, temporal, and occipital connections. Because the symptoms disappeared over time, we conclude that the transcallosal surgical approach can, in the long term, be considered a relatively harmless method. (Neurosurgery25:442‐447, 1989)