The European Organisation for Research and Treatment of Cancer (EORTC) has carried out clinical trials for nearly 30 years. During this time, several disease-oriented groups within the EORTC have been shaped by rapidly changing regulations in the area of drug development. Continual networking, dissemination of knowledge, and the establishment of specialized administrative units have allowed the EORTC to play a leading role in the development of improved treatment options for patients with brain tumors. Recently, the EORTC Brain Tumor Group and the EORTC New Drug Development Group have been integrated to create a network of institutions dedicated to screening new chemotherapy agents for the treatment of high-grade gliomas. Indeed, several new regimens and agents have already been investigated by this collaboration. Most notable are the recently closed study on temozolomide (Temodar [US], Temodal [international]; Schering-Plough Corporation, Kenilworth, NJ) in the adjuvant setting and in combination with radiotherapy in patients newly diagnosed with glioblastoma multiforme, and the ongoing study on oral STI571 for the treatment of gliomas. Within the current networks, a well-defined strategy has been implemented to select specific and targeted agents for the drug screening process. By sharing their expertise with the EORTC networks, medical oncologists, neuro-oncologists, and radiologists can assist in the clinical development of potentially active agents in patients with brain tumors.