Cardiopulmonary bypass (CPB) is related to inflammatory response and pulmonary dysfunction. The aim of this study was to evaluate the effects of CPB leukocyte filtration on inflammation and lung function after coronary artery bypass grafting (CABG). A prospective randomized study was performed to compare CABG patients undergoing CPB leukocyte filtration (n = 9) or standard CPB (n = 11). Computed tomography, oxygenation, leukocyte count, hemodynamic data, PaO2/FiO2, shunt fraction, interleukins, elastase, and myeloperoxidase were evaluated. Data were analyzed using two-factor ANOVA for repeated measurements. The filtered group showed lower neutrophil counts up to 50 min of CPB, lower shunt fraction up to 6 h after surgery, and lower levels of IL-10 at the end of surgery (p < 0.05). There was no statistically significant difference between groups related to other parameters. Leukodepletion during CPB results in neutrophil sequestration by a short time, decreased IL-10 serum levels, and lower worsening of lung function only temporarily.