In 60 angulated fractures of the humeral shaft, the 'U' slab acted as a dynamic splint to reduce the deformity without causing distraction and delayed union. The reduction occurred as effectively as manipulation under anesthesia. The forces acting with the slab produced minor varus deformity, but this affected neither the cosmetic nor functional results. Functional recovery was relatively rapid in patients younger than 35 years of age. The fracture was associated with a high overall complication rate related to the severity of the causal trauma. Radial nerve palsy was the most common complication and when present, was noted at initial examination. Radial palsy was associated with severe trauma, producing fractures around the lower third of the shaft, and recovered spontaneously. In no instance did palsy result from the treatment. The 'U' slab method is simple, effective, without significant complications, and has the advantage of being applicable when general anesthesia is contraindicated.