The treatment of brain stem gliomas has evolved over the last few decades, reflecting advances in imaging (MR), microsurgical techniques and biological understanding. The aim of this chapter is to provide a preoperative classification for intrinsic brain stem lesions that will predict histopathology and biological behavior from the clinical syndrome and the MR appearance. Such a classification system may help in selecting children with brain stem tumors that can benefit from surgery. Technical considerations, potential surgical complications, and the ways to avoid them are discussed.