Medical coma in the course of an illness traditionally implies a poor prognosis, but few data define the factors responsible for this. The identification of these factors will enable physicians and other health care providers to identify comatose patients most likely to regain meaningful function with proper therapy, and thus enhance patients' care decisions and resource allocation, This study was undertaken to determine the factors that affect the prognosis of medical coma in lbadan, Nigeria. STUDY DESIGN/METHODS The level of consciousness and brainstern functions of 200 patients admitted in medical coma were assessed at admission, 6 hours later, then daily for 7 days, on the 14th day, the 21 day and finally the 28th day, after which the best outcome was recorded. The Glasgow Coma Scale and brainstern sign score were used to determine the neurologic status while information from biodata, relevant history of illness, time of presentation to the University College Hospital, lbadan, time of diagnosis and treatment, results of investigations and questionnaires were used to identify other prognostic factors. RESULTS Medical coma constituted 9.8% of emergency admissions, 3.1% of total admissions and 16.8% of deaths in University College Hospital, lbadan during an 8-month study period. The common causes were hemorrhagic stroke, diabetic and uremic coma and meningitides. Hypertension, hyperglycemia, obesity, HIV and hepatitis B viral infections were the predisposing factors identified. Aspiration pneumonia was the commonest co-morbid illness. Multivariate analysis showed that the most significant prognostic factors were delayed presentation, family knowledge of cause of coma, family support, cause of coma, Glasgow Co