Although weight reduction can have a favourable effect on glucose control among persons with diabetes mellitus (DM), no national data have been used to describe weight loss among persons with DM. To address this gap, national survey data were used to assess self-reported weight loss among persons from the USA with and without DM and to identify how other factors might interact with DM to increase the risk of weight loss. Data from the 1989 United States National Health Interview Survey were analysed for 2185 persons with DM and 18 304 persons without DM. Fifty-five percent of persons with DM reported they were attempting weight loss compared with only 43% of persons without DM. Among those who attempted weight loss, one-quarter of persons with DM lost at least 15 lb (approximately 5.6 kg) during the prior year compared with only 16% of persons without DM. After multivariate adjustment for demographic variables, health care utilization, cigarette smoking, and degree of overweight, persons with DM were 1.7 times more likely to have lost 15 lb than were persons without DM. Among persons with DM, having been hospitalised twice and having consulted a dietitian or nutritionist during the prior year were both related to intentional weight loss. Further research is needed to clarify the roles of health status and medical resources in weight loss effort and success.