DNA SIMDEX is a DOS-based computer program designed to assist in the visual scoring of DNA fingerprint assays. DNA SIMDEX uses the migration distances of the individual DNA bands to generate lists of probable matching and nonmatching bands and automatically calculates a probable similarity index between DNA fingerprints based on these initial predictions. After comparisons are edited by the user, the final similarity index, along with accompanying data, can be saved on a floppy disk or hard drive for easy storage and retrieval or can be printed directly on a laser or line printer. The program has been developed to function with or without an image-analysis system, thus making it an inexpensive alternative for small laboratories.