BACKGROUND.: In immediate implant-based breast reconstruction (IBBR), large variation is observed in current practices between a direct-to-implant and a two-stage approach (insertion of a breast implant after a tissue expander). This population-based study aimed to compare unplanned short- and long-term revision incidence between direct-to-implant and two-stage IBBR in the Netherlands. METHODS.: All patients with immediate IBBR following a mastectomy between 2015 and 2019 were selected from the nationwide Dutch Breast Implant Registry (DBIR). Short- and long-term unplanned revision incidences were studied per immediate IBBR, including revision indications and the total number of additional operations. Confounding by indication was limited using propensity score matching. RESULTS.: A total of 4512 breast implants (3948 women) were included, of which 2100 (47 percent) for direct-to-implant IBBR and 2412 (53 percent) for two-stage IBBR. Median (IQR) follow-up was 29 (16-45) months and 33 (21-47) months, respectively. Short-term revision incidence was 4.0 percent and 11.7 percent, respectively (conditional OR 0.31, 95 percent CI 0.23-0.42). Long-term revision incidence was 10.6 percent (95 percent CI 9.2-12.1) and 16.4 percent (95 percent CI 14.8-17.9), respectively. In the propensity score matched cohort, similar results were found. In the direct-to-implant group, more breasts were reconstructed within the planned number of operations than in the two-stage group. CONCLUSION.: Unplanned revision surgery occurred less often after direct-to-implant IBBR, and more breasts were reconstructed within the planned number of operations compared to two-stage IBBR. These results, based on real-world data, are important for improving patient counseling and shared decision-making.