Maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) were measured long after lung resection with reference to operative procedure and vital capacity (VC). MIP and MEP were measured before surgery and 3 months after surgery in 80 patients who underwent lung resection. The procedures were pneumonectomy in 4 cases, lobectomy in 42 cases, segmentectomy in 3 cases, and wedge resection in 31 cases. Postoperative MIP, MEP, and VC were expressed and analyzed as percents of their respective preoperative values (MIP(%), MEP(%), VC(%)). Patients who underwent lobectomy had significantly lower MIP(%) and MEP(%) than did those who underwent wedge resection (p < 0.001). Both MIP(%) and MEP(%) correlated significantly with VC(%) (p < 0.001). Pulmonary resection can continue to affect both pulmonary function and respiratory muscle strength even 3 months after surgery.