We studied the timing and progression of foot and ankle changes in 81 children with genetically confirmed Charcot–Marie–Tooth disease type 1A (CMT1A) and determined their impact on motor function and walking ability. Foot deformity, weakness, pain, cramps, and instability were a common feature of CMT1A. Foot structure evolved toward pes cavus from early childhood to adolescence, although a subgroup with normal and planus feet remained. Foot strength increased with age, although compared to age‐equivalent norms it declined from 4 years. Factors associated with evolving foot deformity included muscle weakness/imbalance, restricted ankle flexibility, and joint hypermobility. Regression modeling identified dorsiflexion weakness, global foot weakness, and difficulty toe‐walking as independent predictors of motor dysfunction, while pes cavus and difficulty heel‐walking were predictors of poor walking ability. Foot problems are present from the earliest stages of the disease and can have a negative impact on function. Early foot and ankle intervention may prevent long‐term disability and morbidity in CMT1A. Muscle Nerve 39: 158–166, 2009