A 9-year-old 390 kg games pony presented with acute onset of grade 5/5 (AAEP) right hindlimb (RH) lameness. During clinical examination, the source of lameness was localised to the tarsal region. Radiographic examination identified a closed, simple, nondisplaced, incomplete fracture of the calcaneal shaft. The pony was initially treated with box rest; however, despite an initial good response, the horse represented with a grade 5/5 (AAEP) RH lameness, 2 weeks after initial presentation. The decision was made to treat the fracture using a tarsal sleeve cast extending from mid-third of the tibia/crus to the level of distal metatarsus. The cast was replaced every 2 weeks and maintained for a total of 8 weeks. After cast removal, the horse was kept on strict box rest for 3 weeks. After discharge from the hospital, in-hand walking exercise from the stable was commenced and gradually increased over a 4-week period. The horse was then gradually reintroduced to small paddock turnout exercise for eight further weeks. The horse was able to return to full athletic function. Conservative treatment using a tarsal sleeve cast should be considered only in horses presenting an incomplete nondisplaced fracture of the calcaneal shaft.