To assess the importance and severity of measles in the Port Moresby area, 101 cases seen in hospital Out-Patients, and 26 cases seen in urban clinics during 1974, and 277 cases admitted during 1973-74, are analysed. The majority of cases were in children under 3 year of age. Of the 101 out-patients, only 19 had uncomplicated measles. 61 had pneumonia and 28 had gastro-enteritis. 19 needed admission to hospital. There were no deaths. Of the 277 admitted patients, 73% had pneumonia, 26% had gastro-enteritis and 22% were dehydrated. There were 6 deaths (a case mortality rate of 2.2%). All the children who died had pneumonia; 4 children developed tuberculosis. The disease appears to be more severe in Papua New Guinea than in most developed countries tough less severe than in many other developing countries. We estimate that the cost of treating measles is about K25,205 per annum. The introduction of measles vaccination might reduce the cost of measles to the community by K14,000 per annum, and would save children from an unpleasant and often serious disease.