Objective. To define the patient perspective of what constitutes a failure of total joint replacement (TJR) in a qualitative study. Methods. We used the nominal group technique (NGT) with participants who had undergone elective total hip replacements (THR) and/or total knee replacements (TKR) to answer the question, "When would you consider a knee or hip replacement to be a failure?" Results. We performed 8 nominal groups with 42 participants, all of whom had undergone THR and/or TKR between 2016 and 2018. Of these, 48% were male, 17% were Black, 79% had college education or above, and 76% had had osteoarthritis as the underlying diagnosis. The nominated responses/themes that were ranked the highest by the participants were as follows: (1) refractory index joint pain (80 votes); (2) occurrence of postoperative adverse events (54 votes); (3) unable to resume normal activities or go back to work (38 votes); (4) little or no improvement in quality of life (35 votes); (5) early revision surgery (35 votes); (6) death (7 votes); and (7) other, including nurse or physician negligence (2 votes) and expectation-outcome mismatch (1 vote). Conclusion. Lack of relief of pain or restoration of function or quality of life, or the occurrence of surgical complications after TJR were defined as TJR failure by participants. Functional TJR failure seems as important or more important than surgical failure. This patient perspective emphasizing pain, function, satisfaction, adverse events, and revision as critical domain components of TJR failure independently validated their inclusion in the TJR core domain set for clinical trials in people undergoing knee or hip TJR.