Chronic ankle instability (CAI) is associated with sensorimotor deficits, which may affect dynamic complexity by constraining the postural control system. Stochastic resonance stimulation (SRS) may restore sensory function and promote healthy postural control dynamics. This study used Sample entropy (SampEn) during quiet single- and double-leg stance to examine the impact of CAI on center of pressure velocity (COPV) dynamics and the effects of SRS on COPV dynamics in individuals with CAI. Group differences in baseline SampEn were observed in double-leg resultant COPV, single-leg mediolateral COPV, and single-leg resultant COPV (Chronic ankle instability (CAI) is associated with sensorimotor deficits, which may affect dynamic complexity by constraining the postural control system. Stochastic resonance stimulation (SRS) may restore sensory function and promote healthy postural control dynamics. This study used Sample entropy (SampEn) during quiet single- and double-leg stance to examine the impact of CAI on center of pressure velocity (COPV) dynamics and the effects of SRS on COPV dynamics in individuals with CAI. Group differences in baseline SampEn were observed in double-leg resultant COPV, single-leg mediolateral COPV, and single-leg resultant COPV (P< .05). For single-leg mediolateral and resultant COPV, SampEn in the CAI group with SRS was not different than SampEn in the control group without SRS (P> .05). These findings suggest that CAI is associated with changes in behavioral complexity and that SRS may restore complex COPV dynamics in individuals with CAI. [Athletic Training & Sports Health Care.2014;6(x):xxx–xxx.]