Patients undergo stereotactic biopsy of brain tumor followed by CT guided stereotactic placement of 2 intratumoral catheters on day 0. Patients with histologically confirmed malignant glioma receive interleukin-13 PE38QQR immunotoxin interstitially over 96 hours beginning on day 1. Patients with a residual enhancing mass undergo repeat catheter placement on day 56 and then receive a second interstitial infusion beginning on day 57 in the absence of disease progression or unacceptable toxicity.