455 Background: Patients undergoing esophagectomy frequently experience malnutrition, which in combination with the catabolic effects of surgery can result in loss of muscle mass and function. Safe swallowing requires the preservation of muscle mass. Modified barium swallow (MBS) enables assessment of postoperative swallowing impairments. We assessed the incidence and risk factors of swallowing dysfunction post-esophagectomy. Methods: Patients with a MBS post-esophagectomy were identified between January 2015-June 2019 at Levine Cancer Institute at Carolinas Medical Center. Swallowing was evaluated with the Penetration Aspiration Scale. Muscle loss was evaluated with pre-operative hand-grip strength (HGS) and skeletal muscle index (SMI) and skeletal muscle density (SMD) from axial CT images. Uni- and multivariable GLM analyses were performed. Results: 91 patients (79 men, 12 women) underwent esophagectomy with an average age of 64.0 + 10.1. Pre-operative HGS, SMI, and SMD all decreased with age. Significant differences existed between sexes in HGS, SMI, and SMD, so the cohort was stratified by sex for analysis. Univariate analysis of male patients revealed older age, lower body mass index (BMI), smoking history, prior feeding tube, and lower pre-operative HGS and SMI were associated with aspiration or penetration on MBS. Among women, no factors analyzed were significantly associated with swallowing dysfunction. Conclusions: Swallowing dysfunction after esophagectomy is correlated with increased age and lower BMI. The role of muscle loss in the risk of aspiration after esophagectomy is not clear. Further research is needed to determine the relationship between these factors with the goal of enabling preoperative physiologic optimization and patient selection. [Table: see text]