BACKGROUND: We analyzed patient outcomes after deep inferior epigastric perforator (DIEP) flap reconstruction using a national database to assess readmission, mortality, morbidity, and length of stay (LOS). METHODS: This retrospective cohort study utilized the 2017-2020 Nationwide Readmissions Database. Patients had an International Classification of Diseases, Tenth Revision procedure code for DIEP flap reconstruction from January to November each year. The primary outcome was the 30-day readmission rate, with secondary outcomes including in-hospital and 30-day mortality, reasons for admission and readmission, and complication rates. Multivariate regression adjusted for confounders. RESULTS: A total of 32,019 DIEP flap reconstructions were identified, with a median patient age of 51 years. The most common indication was breast reconstruction after mastectomy. In-hospital, 30-day, and calendar-year mortality rates were all under 1% (95% confidence interval [CI]: 1.29-3.99). The 30-day readmission rate was 5.8% (95% CI: 5.4%-6.3%), with infection being the leading cause of readmission (2.0%), a previously unreported finding. Other causes included wound dehiscence (0.19%), pulmonary embolism (0.19%), sepsis (0.18%), and hematoma (0.18%). Reoperation rates were 7% during the index hospitalization and 11% during readmission. The average LOS was 3.7 days (95% CI: 3.65-3.82), consistent with current literature. CONCLUSIONS: This study provides valuable insights into DIEP flap reconstruction outcomes, revealing a 2.0% infection readmission rate. It shows a higher overall readmission rate (7% versus 5.6%) and a lower dehiscence rate (0.2% versus 2.8%) compared with previous data. These findings, derived from the largest nationally representative readmission database in the United States, also demonstrate comparable reoperation rates and LOS.