I report on the occurrence and metabolic correlates of obesity among the Inuit (Eskimos) of the central Canadian Arctic using data from the Keewatin Health Assessment Study conducted during 1990 and 1991 in eight Inuit communities in the Northwest Territories (n = 434, adults aged 18 years and older). Data from the 1990 Manitoba Heart Health Survey among 2200 predominantly white residents of the province of Manitoba were used for comparison. Judging by body mass index and two skinfold thicknesses, obesity among the Inuit is as prevalent as it is in the general North American population. This is a new development over the past two or three decades, the result of rapidly changing physical activity, diet, and lifestyle. Obesity is more prevalent among women, among whom there is also a higher degree of central fat patterning based on the waist-to-hip ratio. When different categories of obesity are compared, blood pressure and one or more of the lipids show an increasing trend but glucose or insulin level shows no significant change. This observation distinguishes the Inuit from other populations. Even where a relationship exists, as with triglyceride and HDL cholesterol levels, the magnitude of the response is lower among the Inuit. The differential effect of obesity on glucose, blood pressure, and lipid levels in the Inuit compared with non-Inuit suggests a type of selective insulin resistance, the underlying mechanism of obesity and several chronic diseases. Inuit metabolism reflects their almost exclusive diet of fat and proteins traditionally. From the public health perspective it is important to monitor and ameliorate the impact of changing diet and physical activity on the prevalence of obesity and associated health effects.