Stress fracture of the tarsal navicular bone is now frequently recognised. The majority of navicular stress fractures are partial fractures in the sagittal plane. They occur mainly in track and field athletes. A number of theories regarding the aetiology of this fracture have been proposed. Athletes with a history of vague, activity-related midfoot pain, with associated tenderness over the dorsal proximal navicular ('N' spot) should be suspected of having a navicular stress fracture. Plain radiography frequently fails to demonstrate the fracture, thus radionuclide scanning is the investigation of choice to detect navicular stress injury. A computed tomography (CT) scan should be performed to confirm the presence of the fracture. Various methods of treatment have been employed. A minimum of 6 weeks of strict non-weightbearing cast immobilisation is the treatment of choice. After removal of the cast, a further 6 week programme of rehabilitation with a graduated return to activity, joint mobilisation and soft tissue massage is required. Surgery for nonunion or delayed union is rarely required if initial treatment is appropriate.