Obesity affects a disproportionate proportion of total knee arthroplasty (TKA) patients. Our study explores pre-operative characteristics between obese and non-obese patients undergoing TKA surgery. A cohort of 4718 osteoarthritic patients, undergoing primary TKA, was studied. Patients were stratified according to BMI classes. Each class was compared in terms of age, race, gender, level of education, insurance status, pre-operative WOMAC, SF-36, and Elixhauser comorbidities. There was a positive relationship between BMI and female gender, non-white race, Medicaid, private insurance, and self-pay. A negative relationship was observed between BMI and age, Medicare, WOMAC and SF-36. Obese TKA candidates differ from their non-obese counterparts in a number of demographic, socioeconomic, and clinical characteristics.