Previously, we reported a good clinical treatment effect of intrathecal chemotherapy by repeated bolus administration of 5-fluoro-2'-deoxyuridine (FdUrd) for neoplastic meningitis (NM). Moreover, we detected no side effects or neurotoxicity despite the long-term repetition of intrathecal administration. On the basis of these findings, continuous intrathecal chemotherapy (CIC) with FdUrd for patients with NM was attempted using a simple pump system. We evaluated the usefulness of CIC with FdUrd for the treatment of NM. A total of 25 patients were enrolled in this study. FdUrd (1.0 mg/d) was administered using a balloon pump system. CIC was continued as long as possible. Eight patients received whole-brain irradiation (3 Gy x 10) simultaneously with CIC. The effects of the treatment were analyzed in terms of improvement in neurological signs and symptoms and the findings of ventricular and lumbar cerebrospinal fluid analysis 2 and 4 weeks after CIC was initiated and on magnetic resonance imaging scans 2 months after CIC began. No apparent toxicity has been observed to date. Evidence of a cerebrospinal fluid response was observed in 13 patients. Headache and nausea were improved in all patients, and cranial nerve impairment was improved in 12 patients. A magnetic resonance imaging response was observed in only 5 patients. Overall response was observed in 15 patients when cases of stable disease were excluded from the responding cases. Survival time from the commencement of CIC (mean +/- standard error of the mean) was 255 +/- 30 days in 25 patients. This therapy may be useful, especially as a maintenance therapy for NM.