Cerebrospinal fluid examination was carried out in 45 corpes, the results being related to the time elapsed from death till the sample's collection (TOC). The cases were distributed in three groups: 1 — cases with TOC till four hours; 2 — cases with TOC from four till eight hours; 3 — cases with TOC of eight hours or more. The CSF samples were submitted to investigations concerning to the cytology, the concentrations of chlorides, glycosis, urea and total proteins, the protein profile and the activities of glutamic-oxalacetic (GOT) and glutamic-pyruvic (GPT) transaminases. It was found that the presence of red blood cells became more frequent and that the number of hematiae tended to be higher with the increase of the TOC. The number of red blood cells in the sample indicates the degree of CSF and blood mixture, the evaluation of data proper to CSF composition being impaired by mixture. So, the evaluation of the changes that may be considered proper to the CSF in the post-mortem was carried out only in the samples presenting no more then 1,000 hematiae per mml. Normal white cells number was proportionally more common in the third group of cases. Pleocytosis was more frequently found than normal cell count. It was slight or discrete in most of the cases. More than 50 white cells per mml were found in the samples collected from cases in which the patients had died in the course of acute infections. Low concentrations of chloride and glycosis were found in most of the cases and they tended to be lower with the increase of TOC. Hipoglycorrhachia was found to be more intense in the cases with pleocytosis. The concentration of urea was high in most of the cases; the increase of urea contents was at the same range in the three groups of cases considered. High GOT and GPT activities were found in several cases and the TOC appeared to influence the increase of these activities. This influence was more conspicuous in the last group only for GPT. Total protein concentrations above normal were frequent. They tended to be more conspicuously elevated with the increasing of TOC. The protein profiles were marked by the inversion of albumin/globulins ratio. They tended to be of the mixed type, with increase in the alpha and/or gamma globulins participation. The gamma globulin increase was more frequently observed. The increase of these globulin fractions was more conspicuous in the cases refering to patients who died during infectious diseases. An increase of the beta globulin fraction was observed in four cases: in two the death occurred in the course of hepatic cyrrhosis and, in two, of neoplasies. The influence of TOC on the protein profile changes was discrete: with the increase of the TOC the participation of gamma globulin increased and that of beta globulin decreased. The aspects of CSF composition here considered allow the conclusion that many of the changes are delineated during the first 4 hours after death, being more conspicuous those related to cell contents and chloride, glycosis and urea concentrations.