This double-blind, sham-controlled study sought to investigate the effectiveness of cranial electrotherapy stimulation (CES) for the treatment of bipolar II depression (BD II). After randomization, the active group participants (n = 7) received 2 mA CES treatment for 20 minutes five days a week for 2 weeks, whereas the sham group (n = 9) had the CES device turned on and off. Symptom non-remitters from both groups received an additional 2 weeks of open-label active treatment. Active CES treatment but not sham treatment was associated with a significant decrease in the Beck Depression Inventory (BDI) scores from baseline to the second week (p = 0.003) maintaining significance until week 4 (p = 0.002). There was no difference between the groups in side effects frequency. The results of this small study indicate that CES may be a safe and effective treatment for BD II suggesting that further studies on safety and efficacy of CES may be warranted.