OBJECTIVES: Cachexia, a complex wasting syndrome of the muscle tissue, is a serious sequela of many chronic diseases, including cancer and COPD. In general, cachexia is associated with higher inpatient mortality and longer length of stay. Little is known about the effects of cachexia in orthopedic surgical patients.  The purpose of this study was to compare the perioperative outcomes of primary total joint arthroplasty (TJA) between patients with and without cachexia. METHODS: Patients undergoing TJA were identified in the 2002-2012 Nationwide Inpatient Samples using International Classification of Diseases, 9^thRevision, Clinical Modification  (ICD-9-CM) procedure codes for total hip arthroplasty (81.51) and total knee arthroplasty (81.54). Patients with cachexia (ICD-9-CM diagnosis code 799.4) were greedy matched on age, gender, primary diagnosis, procedure, and pre-operative severity to TJA patients without any weight or nutritional deficiencies (i.e., without ICD-9-CM diagnosis codes 262, 263.0, 263.1, 263.9, 269.8, 269.9, or 783.22). Length of stay and incidence of in-hospital mortality, major perioperative complications, and minor perioperative complications were then compared between patient groups. A total of 479 patients with cachexia undergoing TJA were identified (median age 76 years [IQR 62-83]).  RESULTS: Exact matches were identified for 308 cachexia patients (64%) (median age 76 [IQR 62.5-83]). Cachexia patients were nearly three times as likely to experience major surgical complications (11.7% versus 4.6%, RR=2.57 [1.42-4.67], p<.01) and over five times as likely to die during the hospital stay (3.6% versus <1%, OR=5.50 [1.23-24.63], p=0.01) than patients without cachexia. There was no statistical difference for minor surgical complications between patient groups (9.7% overall, p=0.17). Patients with cachexia tended to stay one day longer than patients without cachexia (4 vs. 5 days, p=0.01). CONCLUSIONS: Cachexia significantly increases the risk of major surgical complications and in-hospital mortality in patients undergoing TJA. Providers can use this information for patient consultation and pre-operative patient education and informed consent.