Objectives: Little to no long-term data exist following mosaicplasty/osteochondral autograft transfer (OATS). The purpose was to assess the long-term outcomes of osteochondral autograft transfer in terms of patient-reported outcomes, reoperation rates, and conversion to arthroplasty. Methods: Between September 1999 through April 2021, 63 patients who underwent mosaicplasty were queried from an institutional cartilage registry with patient reported outcome measures (PROMs), including the 36-Item Short Form Survey (SF-36), the Knee Outcome Survey Activities of Daily Living Scale (KOS-ADLS), and the International Knee Documentation Committee Subjective Knee Form (IKDC) for OATS surgical procedures from the practice of six fellowship-trained knee specialists. Inclusion criteria were patients treated with mosaicplasty with preoperative PROMs and minimum two-year follow-up. Exclusion criteria were prior ipsilateral surgical procedures, advanced osteoarthritis, revision cartilage procedures, inflammatory arthropathy, or loss to follow-up. The preoperative and minimum two-year clinical outcomes with respect to the SF-36 score, reoperation rates, and conversion to arthroplasty were analyzed Results: Mean age was 27.4 ± 12.4 years and 20/63 (31.7%) were female with a mean follow-up of 5.7 ± 3.2 years. The mean lesion size was 2.3 ± 1.6 cm2 requiring a mean of 2.2 ± 1.3 autograft plugs. Mean IKDC and KOS-ADL increased from 46.4 ± 15.1 and 64.4 ± 16.3 preoperatively to 70.4 ± 22.6 and 83.8 ± 11.7, respectively, at 10-year follow-up. A total of 69% and 67% surpassed the MCID and SCB1,2, respectively, for IKDC at 2-year follow-up; similarly, 60% and 33.3% surpassed MCID and SCB, respectively, for IKDC at 10-year follow-up. The overall reoperation rate was 28.6% at a mean of 43.8 years with partial meniscectomy, chondroplasty, and loose body removal most commonly performed. Two patients required arthroplasty conversion. Conclusions: OATS remains a durable knee preserving cartilage repair operation with low incidence of reoperation 10 years following index procedure.