The clinical and functional characteristics of patients with severe obesity who present for non-bariatric surgery have rarely been described. For this study, 293 such patients (mean body mass index 42 kg/m2) were investigated using their medical records, a 6-minute walk test, N-terminal pro B-type natriuretic peptide measurement, and the World Health Organization Disability Assessment Schedule 2.0 measure of disability. Cardiorespiratory disease and diabetes were common, with blood tests revealing a high probability of additional unexpected and undiagnosed renal and cardiac disease in a significant proportion of patients. One-third of patients had natriuretic peptide values that identify early left ventricular dysfunction in the community, with 16% above a value described as useful in predicting adverse outcomes for elective surgical patients. Only 10% of patients walked a distance within 10% of that predicted in six minutes, and 22% did not complete the test. Over one-third of patients (34%) had a clinically significant level of disability, with those unable to walk for six minutes describing higher levels of disability. Functional capacity as measured by the 6-minute walk test was significantly lower than would be expected from age, gender, and weight alone, and was related to age and degree of disability but not body mass index. We describe a severely obese population presenting for non-bariatric surgery who had significant levels of comorbid disease, functional impairment, and disability that were not apparent on routine preoperative assessment.