A guide to facilitate the insertion of a straight Küntscher nail in the treatment of tibial fractures is described, as well as the techniques for insertion of the nail. Criteria for the selection of cases, differences in the anatomy of the bone at its ends and in its middle, and the technical factors of nail size and placement are similar to those widely accepted for femoral nailing. The method has been used in thirty fractures. All united under early resumption of full weight-bearing and complications were infrequent.