Aim: Evaluation of the Nativis Voyager® device in patients with recurrent glioblastoma (rGBM). Materials & methods: Voyager is a noninvasive, nonthermal, nonionizing and portable investigational device which delivers ultra-low radio frequency energy ( ul RFE®) that uses a magnetic field to penetrate tissues to alter specific biologic functions within cells. Patients with rGBM were treated with Voyager alone (V) or Voyager in combination with standard of care (V + SoC). Safety and clinical utility were assessed every 2–4 months. Results: Data from the first 11 patients treated are reported here. Median progression-free survival was 10 weeks in the V arm and 16 weeks in the V + SoC arm. Median overall survival was 16 months in V arm and 11 months in the V + SoC arm. No serious adverse events associated with the device were reported. Conclusion: These data suggest that the Voyager is safe and feasible for the treatment of rGBM.