The records of all patients who died in the medical wards of the University Teaching Hospital in Papua New Guinea during a 6-month period between 1st January and 1st July 1984 were reviewed. Deaths were classified as early or late and subclassified as preventable, treatable, untreatable or undetermined. There were 120 deaths among 1242 adult patients admitted to the medical wards during the period under study (overall case fatality rate 10%). 35 patients died within 24 hours after admission (early death), 2 of preventable, 7 of treatable, 8 of untreatable and 18 of undetermined causes. Of patients who stayed alive in the hospital for more than one day, 5 died of preventable, 28 of treatable, 23 of untreatable and 29 of undetermined causes. Autopsy was performed on 3 patients (2.5%). Age of the deceased patients ranged from 13 to 67 years (median: 37). Male to female ratio was 1.86. The length of hospital stay ranged from 1 to 77 days (median: 4). Infectious diseases were found to be the major cause of death with pneumonia and tuberculosis leading the list. The emergency procedures, laboratory facilities and autopsy rate need to be improved to reduce the number of deaths from undetermined and preventable causes in Papua New Guinea.