This report presents data demonstrating a simple method that can potentially be extended to a wide range of cloning strategies to increase the yield of insert-containing recombinants. The method requires that the ligation of an insert to a vector does not regenerate the original restriction enzyme recognition sequence. In the example presented, PCR products were blunt-end ligated to a SmaI-cut vector, in the presence of SmaI endonuclease. The addition of the restriction enzyme to the ligation reaction dramatically favored the ligation of insert to vector rather than vector self-ligation.