Multiple single-institution studies have revealed that breast free flap compromise usually occurs within the first 48 postoperative hours. However, national studies analyzing the rates and timing of breast free flap compromise are lacking. This study aimed to fill this gap in knowledge to better guide postoperative monitoring. All women undergoing breast free flap reconstruction from the American College of Surgeons National Surgical Quality Improvement Program 2012 to 2016 database were analyzed to determine the rates and timing of free flap take-back. Take-backs were stratified by postoperative day through the first month. Multivariable modified Poisson regression analysis was used to determine the independent predictors of free flap take-back. A total of 6792 breast free flap patients were analyzed. Multivariable analysis revealed that body mass index of 40 kg/m or higher, hypertension, American Society of Anesthesiologists class of 3 or higher, steroid use, and smoking were independent predictors of take-back (p < 0.05). Take-back occurred at the highest rate during postoperative day 1, dropped significantly by postoperative day 2 (p < 0.001), and remained consistently low after postoperative day 2 (<0.6 percent daily). The identified risk factors significantly increased the likelihood of take-back on postoperative day 1 (p < 0.05), with a trend noted on postoperative day 2 (p = 0.06). Fewer than 0.4 percent of patients (n = 27) underwent take-back on postoperative day 2 without having risk factors. This is the first national study specifically analyzing rates, timing, and independent predictors of breast free flap take-back. The data support discontinuing breast free flap monitoring by the end of postoperative day 1 for patients without risk factors, given the very low rate of take-back for such patients during postoperative day 2 (≤0.4 percent). Risk, III.