OBJECTIVES Malignant pleural effusions develop frequently in patients with non-small cell lung cancer (NSCLC), and the prognosis for these patients is very poor. We evaluated the role of systemic chemotherapy for patients with malignant pleural effusions from NSCLC. METHODS We analyzed 34 patients who were found to have malignant pleural effusions in the course of diagnosis of 118 patients enrolled in three consecutive clinical trials on advanced NSCLC assessing combination chemotherapy of cisplatin, ifosfamide, and irinotecan with recombinant human granulocyte colony-stimulating factor support. The objective response in the malignant pleural effusion was evaluated by CT scans every course with the response criteria of the Japan Lung Cancer Society. RESULTS All patients had adenocarcinoma. The pleural effusion showed a complete response in 13 patients, a partial response in 7 patients, and no response in 14 patients. In the assessment of the efficacy of the treatment for the measurable primary or metastatic lesions, there was a partial response in 25 patients, no change in 8 patients, and progressive disease in 1 patient. The response rate in pleural effusions was 58.8%, and overall response in mensurable lesions was 73.5%. The median time to response and duration of response for pleural effusions were 54 days and 151 days, respectively. The median survival time and 1-year survival rates were 362 days and 48.5%, respectively. CONCLUSIONS Both the response rate and survival data in this retrospective study suggest a high degree of activity of this combination chemotherapy in patients with malignant pleural effusions from NSCLC.