A bi-allelic polymorphism in the promoter of the human matrix metalloproteinase-l gene has been reported. It has been found to have a functional effect on the promoter strength and to be associated with risk of cancers. The polymorphism is due to an insertion/deletion of a guanine, and conventional methodologies for genotyping this polymorphism are time-consuming and expensive. A rapid genotyping method based on restriction endonuclease digestion is reported here. (C) 2000 Elsevier Science B.V. /International Society of Matrix Biology. All rights reserved.