We report a patient with nonunion of an isolated fracture of the capitate. A male 17-year-old high school student directly hit the dorsal aspect of the carpal with the wrist in flexion position against another player's shoulder during a rugby football game. Radiographs did not show a fracture of the capitate on the day after the injury, but nonunion was distinct across the waist at the middle one-third of the capitate 4 months later. The fixation using two cannulated Herbert-Whipple screws with iliac cancellous bone graft led to sound union of the capitate and the patient's ability to return to sporting activities. Although the initial plain radiographs do not show a fracture of the capitate, we should consider the capitate fracture and check the patient by repeated physical examinations and radiographs if the patient suffers from persistent localized pain and tenderness over the capitate.