A middle-aged man with progressive myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) was referred for neuromodulation. His condition, likely virally induced decades ago, was characterized by recurring periods of extreme fatigue, lasting months at a time. Medication trials provided partial benefit. Transcranial direct current stimulation (tDCS) was chosen as a neuromodulation treatment, allowing cumulative, ongoing treatment to target ongoing inflammation [1]. Patient was trained with tDCS in the office and then treatment was self-administered at home daily. The protocol was: anode (left dorsolateral prefrontal cortex), cathode (right dorsolateral prefrontal cortex), 2 mA/min, 20 minutes, 40 mA total dose, using 1.5” diameter electrode pads. Patient reported significant benefit early in the day during the first month of daily tDCS. After four weeks, maintenance tDCS sessions were increased to twice daily. Over the next few months the patient experienced full clinical recovery. Follow-up quantitative EEG (qEEG) and neurophysiological testing was done 14 months after initial presentation; pre- and post- comparison studies provide insight into possible treatment biomarkers that may help to explain this patient’s full and unexpected recovery.