Objective <p>The purpose of this study was to determine the association of hypoalbuminemia with adverse outcomes in patients undergoing surgical repair of nonunions or malunions of upper and lower extremity long bones.</p> Methods Design <p>Retrospective.</p> <p><i>Setting:</i> Hospitals participating in American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) from 2005 to 2019.</p> <p><i>Patients:</i> Patients in the ACS-NSQIP database with upper extremity and lower extremity fractures who underwent nonunion or malunion repairs and had preoperative serum albumin levels.</p> <p><i>Outcome Measures and Comparisons:</i> Demographic variables, comorbidities and postoperative complications were collected and compared using t tests and chi squared tests. Multivariate linear regression models were used to assess complications, adjusting for variables such as age, sex, BMI, hospital length of stay, and operation time.</p> Results <p>Univariate analysis of 1640 total patients (338 [20.6%] with hypoalbuminemia and 1302 [79.4%] with normal albumin) showed patients with hypoalbuminemia had significantly increased 30-day mortality rates, increased lengths of stay, and returns to the operating room. Multivariate analysis showed patients with hypoalbuminemia had significantly greater odds for any complication (OR: 2.62; 95% CI [1.77, 3.84];<i> p</i> &lt; 0.001), surgical site infections (OR: 2.62; 95% CI [1.34, 4.99];<i> p</i> = 0.004) and transfusions (OR: 2.77; 95% CI: [1.62, 4.69]; <i>p</i> &lt; 0.001) compared to the normal albumin group.</p> Conclusions <p>There was a significant difference in 30-day postoperative complications between patients with normal albumin levels and those who were hypoalbuminemic after surgical repairs of nonunions or malunions. Albumin level is a risk factor that should be monitored and counseled upon prior to surgical intervention for nonunion or malunion correction.</p> Level of Evidence <p>Level III Retrospective Comparative Study.</p>