AIM--To investigate whether routine formalin fixation of all brains coming to necropsy increases the rate of detection of brain abnormalities relative to either selective formalin fixation of brain tissue or fresh dissection of all brain tissue at the time of post mortem examination. METHODS--A retrospective study of 300 medicolegal necropsies was performed. One hundred cases were examined by doctors with little or no formal training in necropsy pathology. One hundred cases were examined by forensic pathologists, who used their discretion as to whether to fix the brain in formalin. A further 100 cases were examined by neuropathologists; all the brains had already been fixed at the time of necropsy. RESULTS--When examined by doctors with little or no formal necropsy pathology training, only 15% of brains were found to be abnormal. In the case of selective fixation, 33% were found to be abnormal. When there was obligatory fixation of all brains, 51% of all brains were found to be abnormal. CONCLUSIONS--It is concluded that formalin fixation of the whole brain at the time of necropsy, followed by detailed examination of the brain by a neuropathologist, significantly increases the detection rate of brain pathology at necropsy.