38 children between 1 and 10 years of age with femoral shaft fractures were treated by closed reduction and early spica cast with incorporated supracondylar Kirschner wires and followed up prospectively. Overrides of maximum 15 mm, medial and anterior angulations less than 15 degrees and lateral angulation up to 5 degrees were considered acceptable. Posterior angulation and malrotation were not accepted. Of the 38 children examined at a mean of 65.6 months (range, 58-80 months) after fracture, none had any residual skeletal deformity and joint stiffness. At long-term follow-up, maximal shortening was 11 mm and overgrowth was 6 mm. The only factor associated with unacceptable shortening was shortening > 15 mm at the time of spica cast application. We believe that close follow-up during the first 3 weeks after cast application is important in order to achieve an acceptable final outcome. On the other hand this method of treatment is simple, safe and effective. It dramatically decreases hospital stay and cost of treatment and allows rapid return of the patients to their family environment. (C) 1999 Elsevier Science Ltd. All rights reserved.