Purpose The goals of immediate postmastectomy breast reconstruction are to minimize deformity and optimize quality of life as perceived by patients. We prospectively evaluated patient-reported outcomes (PROs) in women undergoing immediate implant-based or autologous reconstruction. Methods Women undergoing immediate postmastectomy reconstruction for invasive cancer and/or carcinoma in situ were enrolled at 11 sites. Women underwent implant-based or autologous tissue reconstruction. Patients completed the BREAST-Q, a condition-specific PRO measure for breast surgery patients, and Patient-Reported Outcomes Measurement Information System-29, a generic PRO measure, before and 1 year after surgery. Mean changes in PRO scores were summarized. Mixed-effects regression models were used to compare PRO scores across procedure types. Results In total, 1,632 patients (n = 1,139 implant, n = 493 autologous) were included; 1,183 (72.5%) responded to 1-year questionnaires. After analysis was controlled for baseline values, patients who underwent autologous reconstruction had greater satisfaction with their breasts than those who underwent implant-based reconstruction (difference, 6.3; P < .001), greater sexual well-being (difference, 4.5; P = .003), and greater psychosocial well-being (difference, 3.7; P = .02) at 1 year. Patients in the autologous reconstruction group had improved satisfaction with breasts (difference, 8.0; P = .002) and psychosocial well-being (difference, 4.6; P = .047) compared with preoperative baseline. Physical well-being of the chest was not fully restored in either the implant group (difference, -3.8; P = .001) or autologous group (-2.2; P = .04), nor was physical well-being of the abdomen in patients who underwent autologous reconstruction (-13.4; P < .001). Anxiety and depression were mitigated at 1 year in both groups. Compared with their baseline reports, patients who underwent implant reconstruction had decreased fatigue (difference, -1.4; P = .035), whereas patients who underwent autologous reconstruction had increased pain interference (difference, 2.0; P = .006). Conclusion At 1 year after mastectomy, patients who underwent autologous reconstruction were more satisfied with their breasts and had greater psychosocial and sexual well-being than those who underwent implant reconstruction. Although satisfaction with breasts was equal to or greater than baseline levels, physical well-being was not fully restored. This information can help patients better understand expected outcomes and may guide innovations to improve outcomes.