A major decline in pulmonary function is observed on the first day after upper abdominal surgery. This decline can reduce vital and inspiratory capacity and can culminate in restrictive lung diseases that cause atelectasis, reduced diaphragm movement, and respiratory insufficiency. The objective of this study was to evaluate the efficacy of preoperative ambulatory respiratory muscle training in patients undergoing esophagectomy. The sample consisted of 20 adult patients (14 men [70%] and 6 women [30%]) with a diagnosis of advanced chagasic megaesophagus. A significant increase in maximum inspiratory pressure was observed after inspiratory muscle training when compared with baseline values (from -55.059 ± 18.359 to -76.286 ± 16.786). Preoperative ambulatory inspiratory muscle training was effective in increasing respiratory muscle strength in patients undergoing esophagectomy and contributed to the prevention of postoperative complications.