We retrospectively investigated the sputum cultures of patients who underwent esophagectomy (n = 104) from just after operation to 11 postoperative days and evaluated the factors which influenced the cultures. We divided the 0-11 postoperative days into three periods (0-3 postoperative days (p.o.d.), 4-7 p.o.d., 8-11 p.o.d.). The sputum cultures were positive at a rate of 56.7% to 65.4% of patients during the period of observation (0-11 p.o.d.). Gram-negative bacillus was mostly detected. MRSA increased time-dependently. Diabetes mellitus, preoperative irradiation recurrent nerve palsy did not influence the positive rate of the sputum cultures. The positive rate of gram-negative bacillus and gram gram-positive coccus in the sputum of the patients who were given sefem-first generation antibiotics was lower than of patients who were given sefem-second generation antibiotics at 8-11 p.o.d. (p < 0.05). The positive rate of gram-negative bacillus in the sputum of patients who underwent esophagectomy with laryngectomy for cervical esophageal cancer was lower than that of patients who underwent esophagectomy without laryngectomy for thoracic or abdominal esophageal cancer at 4-7 p.o.d. (p < 0.05). The positive rate of gram-negative bacillus in the sputum of patients who underwent intraoperative tracheostomy was lower than that of patients who did not undergo intraoperative tracheostomy at 4-11 p.o.d. No patients had pneumonia during the period of observation except for the secondary lung complications. In conclusion, although we have done a good job of management, we should select the appropriate antibiotics with the patient's background in mind.