Gene therapy for neurological diseases is a rapidly expanding field in neurosciences. It has been demonstrated that some viral vectors from HSV-1 (herpes simplex virus type 1), Ad (adenovirus) and AAV (adeno-associated virus) can transfer foreign genes into nondividing cell types (including neurons). In addition, physical/chemical methods are also used in direct in vivo gene transfer. The direct gene transfer techniques will open a new way to study neurophysiology, neuropathology and therapy for neurological diseases at molecular level. They will hopefully lead to surprising progress in gene therapy for neurological diseases.