Stress fractures are common in young and active individuals, associated with aggressive or repetitive physical activity and their early detection is fundamental to optimise patient care, decrease complications and avoid unnecessary exams. Currently, magnetic resonance imaging is the standard of care for detecting these lesions. Recently, ultrasound has been getting an increasing interest for the detection of stress fractures. In this article, we describe a clinical case that involved a second metatarsal stress fracture diagnosed by ultrasound and review the literature regarding the use of ultrasound in the diagnosis of stress fractures, particularly of the metatarsals.