BACKGROUND: Many patients experience bilateral knee osteoarthritis and require bilateral total knee replacement (TKR). Same-stage, bilateral TKR is proposed to be a cost-effective and safe solution compared to two-stage, but conflicting results in the literature are reported. We aim to compare the costs, safety, and rehabilitation performance of patients in same-stage versus two-stage, bilateral TKR with our centre's perioperative protocol. MATERIALS AND METHODS: We retrospectively reviewed 175 patients (95 same-stage, 80 two-stage) who had undergone bilateral TKR in our centre. Patient selection for same-stage, bilateral TKR was strictly protocol-driven and required fulfilment of all criteria, including age < 75 years, American Society of Anesthesiologists (ASA) grade 1 or 2, body mass index (BMI) < 40, and having non-complex arthritis. All patients followed a standardised pre-operative, intra-operative, and post-operative Enhanced Recovery After Surgery (ERAS) protocol. The cost, safety profiles, and rehabilitation outcomes were compared between the same-stage and two-stage groups. RESULTS: The same-stage, bilateral TKR reduced the length of hospital stays by 5.71 days per patient, decreased the operation time by 27.4 min, saved 3.34 (18.6%) physiotherapy sessions, and 3.78 (51.5%) occupational therapy sessions. The same-stage group experienced a higher haemoglobin drop but no significant difference in transfusion percentage, transfusion volume, complication rate, and readmission rate. The two-stage subgroup with anaesthetic risk, age, and BMI similar to the same-stage group showed the same results. Same-stage, bilateral TKR patients experienced no significant difference in final post-operative pain levels and rehabilitation outcomes as two-stage TKR patients. CONCLUSION: This study showed that same-stage, bilateral TKR can reduce costs, with similar safety profiles and rehabilitation outcomes compared to the two-stage, bilateral TKR.