The relative length and height of the lateral and medial walls of the calcaneum probably govern the production and persistence of structural hindfoot deformity, forefoot supination and adduction, and pronation and abduction. Anatomical restoration of the proportions of the calcaneal walls forms the basis of the T-osteotomy of the calcaneum. We have undertaken this operation on 72 feet in 60 patients for cavovarus deformity with forefoot adduction. The calcaneum is approached from the lateral side and the T-shaped osteotomy is performed through the body, the vertical limb being 1 to 1.5 cm behind and parallel to the calcaneo-cuboid joint. The horizontal limb starts from the centre of the vertical cut and ends above the attachment of the tendo achillis. The postero-inferior segment is pushed out correcting the heel varus and at the same time broadening the heel. The forefoot is manipulated downwards and outwards to correct the residual cavus and the adduction and supination of the forefoot. The over-all results, with an average follow-up of 3.7 years, have been satisfactory.