Os intermetatarseum is a relatively frequent accessory foot bone that rarely becomes symptomatic. We present a case of a symptomatic os intermetatarseum in a 12-year-old child, who presented to our clinic with pain during sports and prolonged physical activity. Several months ago, a midfoot sprain had occurred without any detectable fractures. The patient continued to have pain. The diagnosis of a bilateral os intermetatarseum – more prominent on the symptomatic left side – was confirmed with plain radiographs and computed tomography scanning. Surgical resection of the painful accessory bone on the left side was performed. Six weeks postoperatively the patient was asymptomatic and fully returned to sports.