Implantable, biocompatible and biodegradable devices beating an anticancer drug can provide promising local therapy to patients with malignant disorders. With the aim of treating brain tumors, especially gliomas, a membranous sheet containing doxorubicin was produced by co-polymerization to poly(D,L-lactide-co-glycolide) (PLGA). When release of the drug from the sheet was measured, sustained release continued until day 34. The data contrasted with the burst release from material containing a higher proportion of the drug. In terms of biodegradability, a subcutaneous 3 x 3-mm tetragonal sheet was almost completely absorbed by day 80. When a glioma was implanted subcuteneously and the tumor nodule exposed to the sheet, the device inhibited tumor growth significantly. The sheet consisted of an amorphous structure with cavities estimated to have a diameter of 0.5 - 3 mu m by electron microscopic observation. Since the sheet is implantable, biodegradable and has a sustained-drug release property, the device may play a role in the local therapy of brain tumors.