Introduction: Cavus deformity of the foot is defined as equinus (plantar flexion) of the forefoot in relation to the hind foot. In 1/2–3/4 of the children an underlying disease could be diagnosed, usually neuromuscular in origin. Pathomechanism. Gradual developing deformity caused by muscular imbalance, the intrinsic muscles of the foot being weaker as well as the foot dorsiflexors. Main deformities are: claw toes, flexion of the first metatarsal, heel varus and equinus. The deformities will become more rigid with increasing growth and/or progression of the underlying disease. Symptoms are: shoefitting problems, pain, callosities under the forefoot and lateral border, clumsiness during gait and running, tripping. Predominant ages are 8 – 12. Diagnosis: The primary goal is to establish or role out an underlying disease before adequate treatment can be applied. The examination should focus on detailed muscle function and joint mobility. Standardised standing X-ray examination and EMG is often needed for diagnosis and to evaluate muscles to be transferred. Treatment: Moulded insoles, shoe modifications and AFOs are symptomatic. Preventing progression is important. In flexible feet tendon transfers is often sufficient. In rigid deformities various osteotomies is helpful. In the older teenager and adults triple arthrodesis combined with tendon transfers is often needed. Summary: Cavus foot is a common cause for foot problem in the growing child. Neuromuscular dysfunction has to be diagnosed. Surgical procedures are often needed.