In recent years there has been a large increase in the number of morbidly obese persons subject to hospital surgery. In Portugal, 14% of the population of working age is obese. As in other countries these numbers have been rising and it is well known that obese individuals have an increased risk of morbidity and premature death from various diseases. We estimate the impact of obesity on the health sector by calculating the costs of hospital inpatient care associated with obesity in Portugal.