Stress fractures of the tarsal navicular bone are a challenge in diagnosis and therapy. First and foremost you have to think about this fracture. The origin of the injury can be detected in a wrong or too heavy strain of the bone especially in long distance runners and recruits. The MRI is the diagnostic tool of first choice. Therapy of displaced or comminuted fractures as well as pseudarthrosis is best done with surgical procedures like direct screw fixation or interposition of autologous bone depending on the circumstances and the age of injury. Conservative treatment with a plaster of Paris is useful in non-displaced and non-comminuted fractures. Prophylaxis with technical aids and a changing habits is recommended.