This study was conducted in order to re-define the incidence and natural history of postresectional residual pleural spaces (PRS). From 1997 to 2005, 966 patients who were subjected to less than entire lung resections, were followed and any cases of PRS were recorded. The records of these patients were retrospectively analyzed for age, gender, type of resection, side, apical or basal location, size, PRS wall thickness, empyema as well as for bronchopleural fistula occurence, management, and outcome. Postresectional residual pleural spaces outcome was correlated with space characteristics. A total of 92 cases (9.5%) of PRS were documented which developed frequently ( p < 0.001) after upper lobectomies, malignant disease, at an apical location, and on the right side. Unfavorable outcome was strongly correlated with age > 70 years ( p < 0.001), air leak ( p < 0.001), empyema ( p < 0.001), and thickened pleura ( p < 0.001). Good prognosis of PRS was strongly correlated with male gender, apical location, right side, normal pleura thickness, and small size. Postresectional residual pleural spaces of small size without any associated complications should not prolong hospitalization time.