On average, individuals with chronic ankle instability (CAI) are more inverted and have a greater plantar pressure on the lateral column of the foot throughout the stance phase compared to healthy individuals. To date, traditional rehabilitation for CAI has been unable to correct gait deficits associated with CAI. We developed a custom auditory biofeedback device that can be worn in standard athletic shoes that elicits a noise when an excessive amount of pressure is applied to a sensor. PURPOSE: Determine if using this auditory feedback device can decrease lateral plantar pressure in participants with CAI during treadmill walking. METHODS: During this laboratory study, ten participants with CAI (age=21.5, sex (male=3, female=7), height=166cm, mass=65.6kg) completed 30 seconds of baseline treadmill walking using instrumented insoles to measure plantar pressure. Next, the auditory biofeedback device was placed into the shoe under the head of the 5th metatarsal and set to a threshold that elicited audible noise during the participant’s normal gait. Then, participants received instruction to walk in a manner as normal as possible, but elicit no noise, while 30 more seconds of data were collected. Peak pressure of 9 regions of the foot (medial/lateral heel, medial/lateral midfoot, medial/central/lateral forefoot, lesser toes, and the hallux) was compared during shod (baseline) and auditory feedback (AUD FB) conditions using paired t-tests with a priori significance level of P≤0.05. RESULTS: There was a significant reduction in peak pressure in the lateral midfoot (Baseline [Mean±SD]:133.48±24.11kPa vs. AUD FB: 80.67±12.00 kPa, P=0.001), the lateral forefoot (Baseline: 158.97±29.34 kPa vs. AUD FB: 101.20±18.10 kPa, P<0.001), and the central forefoot (Baseline: 176.08±22.23 kPa vs. AUD FB: 146.31±20.25 kPa, P=0.010) during the AUD FB condition. There was a significant increase in peak pressure (kPa) in the hallux (Baseline: 212.70±63.87 kPa vs. AUD FB: 304.38±115.46 kPa, P=0.006) during the AUD FB condition. CONCLUSION: Auditory feedback devices are capable of decreasing lateral pressure during treadmill walking in individuals with CAI. These changes may be advantageous in CAI participants; however, the long-term effects of using this device should be evaluated before providing clinical recommendations.