Background: Following a stroke many patients develop a deformity of the foot referred to as equmus deformity. Equmus deformity is commonly treated by prescribing an ankle foot orthosis (AFO). Few studies have assessed the effects of wearing AFOs or the effects of different types of leaf forms of AFOs on hemiplegic gait. Aim To establish the effects of an equmus deformity of the foot on gait and to examine the effect of wearing AFOs on hemiplegic gait. Methods: 30 normal subjects (Ngroup), 10 normal subject’s age matched with the stroke group (NAMgroup) and 23 stroke patients with equmus deformity of the foot (Sgroup) were recruited to participate in this study. The kinematics and kinetics of each subject’s gait were analysed using a Vicon Motion Analysis system and two AMTI forceplates [250Hz]. Gait was assessed under the conditions of walking 1) without an ankle foot orthosis, 2) with an anterior leaf AFO, and 3) with a posterior leaf AFO. Statistical analyses were carried out using repeated measures ANOVA, correlations and a cluster analysis The p value was set at 0 05. Results: The gait pattern of the Sgroup were described and found to be nonhomogeneous and consisted of three distinct patterns. Only one subgroup (SGI) had significantly improved gait with the wearing of an AFO SGI had the more normalised gait pattern prior to wear of an AFO m comparison to the other two subgroups, having a greater walking speed, stride and step length. Furthermore, this study identified that different leaf forms of AFOs have different effects on joint angular kinematics. Wearing an AFO did not significantly decrease oxygen uptake, energy cost or COM displacement of the Sgroup. Conclusion: The results of this study will aid in improved prescription of AFOs to stroke patients with equmus deformity of the foot. The results of this study would also suggest that wearing AFOs has no significant effect on energy expenditure.