BACKGROUND: Cryolipolysis provides a method for noninvasive fat reduction that significantly reduces subcutaneous fat in a pig model without apparent damage to skin and surrounding structures. This study aimed to determine whether fat reduction in humans caused by cold exposure is associated with alteration in local sensory function or nerve fibers. METHODS: In this study, 10 subjects were treated with a prototype cooling device. Fat reduction was assessed in 9 of the 10 subjects via ultrasound before treatment and at the follow-up visit. Sensory function was assessed by neurologic evaluation (n = 9), and biopsies (n = 1) were collected for nerve staining. RESULTS: Treatment resulted in a normalized fat layer reduction of 20.4% at 2 months and 25.5% at 6 months after treatment. Transient reduction in sensation occurred in six of nine subjects assessed by neurologic evaluation. However, all sensation returned by a mean of 3.6 weeks after treatment. Biopsies showed no long-term change in nerve fiber structure. There were no lasting sensory alterations or observations of skin damage in any of the subjects evaluated. CONCLUSION: Noninvasive cryolipolysis results in substantial fat reduction within 2 months of treatment without damage to skin. The procedure is associated with modest reversible short-term changes in the function of peripheral sensory nerves.