BACKGROUND Removing unwanted body hair is a growing trend in society today, and there are many laserbased devices for hair reduction. There are some limitations to those methods, including the lack of efficacy for lighter color hair. OBJECTIVE The objective was to quantify hair reduction in the axillae after treatment with a noninvasive microwave energy device. MATERIALS AND METHODS A prospective, multicenter study was performed at 3 private dermatology clinics. Fifty-six adult subjects seeking axillary hair reduction were enrolled and treated with the device in 1 or 2 treatment sessions 3 months apart at various energy levels, and followed for 12 months. The primary analysis was monitoring reduction of hair counts from baseline to follow-up visits. A subject assessment of overall satisfaction, odor ratings, and sweat reduction ratings was provided at follow-up visits. RESULTS Fifty-six subjects received treatment, with an average total underarm hair reduction of approximately 70% for both light and dark hair. Percentage of patients with hair reduction of 30% or more was significantly higher than 50% at all follow-up visits. Half of treated subjects reported expected mild transient post-treatment effects such as localized edema, discomfort, and bruising. Other reported events were mild. CONCLUSION This clinical study provides evidence for safe and permanent axillary hair reduction, showing stable average reduction that lasted through the year of follow-up. Most notably, the study has shown the treatment's efficacy for reduction of light-colored axillary hair.