The purpose of this study was to clarify the effects of preoperative inpatient rehabilitation on the incidence of postoperative pneumonia and length of hospital stay in patients with esophageal cancer. Twenty patients were requested for inpatient rehabilitation one week before surgery and 13 patients were used as historical control. The training consisted of respiratory muscle training, lower limb strength training, and aerobic exercise for one hour each in the morning and afternoon for one week. Outcomes are including the length of hospital stay and incidence of postoperative pneumonia. Postoperative hospital stay was 21 days for the intervention group and 35 days for the control group (p = 0.001), and the total length of hospital stay was 28.5 days and 37 days, respectively (p = 0.01). However, the incidence of postoperative pneumonia was 45% and 53.8%, respectively (p = 0.62). Inpatient preoperative rehabilitation for one week is a beneficial measure because it can decrease the hospital stay without adverse events.