BACKGROUND: Repetitive transcranial magnetic stimulation (TMS) is efficacious for acute treatment of resistant major depressive disorder (MDD), but there is little information on maintenance TMS after acute response. OBJECTIVE/HYPOTHESIS: This pilot feasibility study investigated 12-month outcomes comparing two maintenance TMS approaches--a scheduled, single TMS session delivered monthly (SCH) vs. observation only (OBS). METHODS: Antidepressant-free patients with unipolar, non-psychotic, treatment-resistant MDD participated in a randomized, open-label, multisite trial. Patients meeting protocol-defined criteria for improvement after six weeks of acute TMS were randomized to SCH or OBS regimens. TMS reintroduction was available for symptomatic worsening; all patients remained antidepressant-free during the trial. RESULTS: Sixty-seven patients enrolled in the acute phase, and 49 (73%) met randomization criteria. Groups were matched, although more patients in the SCH group had failed ≥ 2 antidepressants (p = .035). There were no significant group differences on any outcome measure. SCH patients had nonsignificantly longer time to first TMS reintroduction, 91 ± 66 days, vs. OBS, 77 ± 52 days; OBS patients were nonsignificantly more likely to need reintroduction (odds ratio = 1.21, 95% CI .38-3.89). Reintroduction lasted 14.3 ± 17.8 days (SCH) and 16.9 ± 18.9 days (OBS); 14/18 (78%) SCH and 17/27 (63%) OBS responded to reintroduction. Sixteen patients (32.7%) completed all 53 weeks of the study. CONCLUSIONS: Maintaining treatment-resistant depressed patients off medications with periodic TMS appears feasible in some cases. There was no statistical advantage of SCH vs. OBS, although SCH was associated with a nonsignificantly longer time to relapse. Those who initially respond to TMS have a strong chance of re-responding if relapse occurs.