Ulnar styloid fractures are frequently ignored in the treatment of wrist fractures in children. Forty-six untreated ulnar styloid fractures (40 tip and six base fractures) associated with radial injuries (45 patients) were retrospectively analysed. At the removal of the cast, we recorded that 80% had a nonunion of the styloid fracture. Thirty-five patients were reviewed at an average of 19 months after treatment. Thirty tip fractures and five base avulsions were found. We recorded 28 patients with a good clinical result despite 21 cases of nonunion, whereas seven patients (all nonunions) had a fair result. All the fair results suffered from intermittent pain during sports and movement, radioulnar joint instability and tears of the triangular fibrocartilage complex. It can be concluded that both distal radius and ulnar styloid fractures should be taken into account in the initial treatment and pain associated with a nonunion of the ulnar styloid in a child may be due to a tear of the triangular fibrocartilage complex.