A stress fracture can be defined as a fracture of a bone caused by repeated (rather than sudden) mechanical stress. They have been reported in almost all bones of the body, with the lower extremity weight bearing bones, especially the tibia, tarsals and metatarsals, being affected most often. These injuries have a broad spectrum of severity and prognosis. Although the pathology of this injury is understood, the aetiology is less agreed upon. This can make it difficult for clinicians to diagnose and treat this common injury. Stress fractures of the proximal tibiae are common in elderly patients with osteoarthritis, and they are also reported in children. Here, we report an unusual case of an otherwise fit, young, adult male who presented with bilateral insufficiency stress fractures occurring simultaneously in both proximal tibiae. Stress fractures should be a differential diagnosis in any young, fit adult who presents with spontaneous knee pain.