America is in the midst of an obesity epidemic, and individuals who have spinal cord injury (SCI) are perhaps at greater risk than any other segment of the population. Recent changes in the way obesity has been defined have lulled SCI practitioners into a false sense of security about the health of their patients regarding the dangers of obesity and its sequelae. This article defines and uses a definition of obesity that is more relevant to persons who have SCI, reviews the physiology of adipose tissue, and discusses aspects of heredity and environment that contribute to obesity in SCI. The pathophysiology of obesity is discussed relative to health risks for persons who have SCI, particularly those contributing to cardiovascular disease. Prevalence of obesity and its comorbidities are discussed and management options reviewed.