This study is a multicenter, randomized double blind, sham controlled study to evaluate the safety and efficacy of H-coil deep transcranial magnetic stimulation (dTMS) as a treatment for patients with major depressive disorder who have been previously unsuccessfully treated with antidepressant medications. Studies of repetitive transcranial magnetic stimulation (rTMS), typically using a figure-8 coil, have shown that stimulating superficial brain regions can be beneficial in treating major depression. Differing from traditional figure-8 coil, the H-coil is designed to stimulate deep brain regions related to motivation, reward, and pleasure. Preliminary studies have been conducted and seem to indicate that through stimulating certain brain areas with the H-coil, dTMS may have an antidepressant effect. The study population will consist of patients with major depressive disorder who have failed adequate medication treatment or shown significant intolerance to medications. The study duration is 18 weeks, with a 2 week period of weaning the patient off medication, followed by 4 weeks of 5 daily treatments and 12 weeks of biweekly treatments. Mood and mental state will be carefully monitored through standard psychological scales and rating during the drug taper-down and throughout treatment.