To investigate whether benign or malignant cells are present in gas evacuated from the abdominal cavity during oncologic laparoscopic surgery. Thirty patients were included in this prospective observational study conducted at an academic, tertiary medical center. Fifteen patients underwent a laparoscopic staging procedure for high-grade uterine adenocarcinoma and 15 patients underwent laparoscopic nephrectomy for suspected renal cell carcinoma. The gas evacuated during laparoscopy was passed through a filter in order to capture any aerosolized cells formed during surgery. After surgery, the filter was rinsed backwards with 50 mL of saline, and the fluid was centrifuged and sent for cytological evaluation. The primary outcome was presence of benign or malignant cells in the rinsed fluid. Neither benign nor malignant cells were identified in evacuated gas in 29 cases (96.7%). In one endometrial cancer case, where macroscopic extra-uterine pelvic metastases were encountered intra-operatively, atypical epithelial cells were found in collected fluid of rinsed gas filter. Gas insufflation during laparoscopy for gynecologic and urologic malignancies apparently does not cause aerosolization and dissemination of malignant cells. However, laparoscopic surgery itself may cause cell spread possibly via surgical instruments when macroscopic, extra-organ tumor spread is encountered, the clinical significance of which remains undetermined.