Loss of skeletal muscle and inferior muscle quality are associated with poor prognosis in patients undergoing preoperative treatment for pancreatic cancer, so maintaining skeletal muscle health before surgery may help accelerate patients’ functional recovery and improve their quality of life following surgery. While exercise helps maintain or increase skeletal muscle in individuals undergoing cancer treatment, its efficacy during pancreatic cancer treatment is unclear. Accordingly, in this study we compared changes in skeletal muscle quantity (skeletal muscle index [SMI]) and quality (skeletal muscle density [SMD]) during preoperative pancreatic cancer treatment in participants in a home-based exercise program (EP) and a historical cohort of patients who received the usual care (UC) with no formal exercise programming. Recommendations for the EP cohort included both aerobic and resistance exercise. We assessed changes in SMI and SMD using computed tomography scans administered at treatment planning (T0, prior to EP enrollment) and preoperative restaging (T1) for 33 EP and 64 UC patients and compared changes between groups. The UC patients had statistically significant SMI decreases from T0 to T1 (-1.4 ± 3.8 cm2/m2; p = .005), while the EP patients did not (0.2 ± 3.2 cm2/m2; p = .7). The SMI loss was significantly worse for the UC than for the EP patients (p = .03). Neither group demonstrated statistically significant changes in SMD from T0 to T1, nor did the groups differ in the amount of change in SMD. An adjusted linear regression model demonstrated that EP participation was significantly associated with better SMI maintenance (p = .02). These results suggest that participation in a home-based EP during preoperative treatment may help improve skeletal muscle health and clinical and quality of life outcomes for pancreatic cancer survivors.