The random amplified polymorphic DNA (RAPD) assay utilizes the polymerase chain reaction (PCR) and short primers of arbitrary nucleotide sequence to amplify DNA. In this study, the RAPD assay was used to identify and map polymorphic markers in the AgResearch International Mapping Flock (IMF) sheep pedigrees. Sires and dams of eight of the full-sib IMF pedigrees were screened with 131 different 10-mer oligonucleotide primers. An average of 85 RAPD polymorphisms was identified between each parental pair, and 53 markers were contributed to the AgResearch IMF collaboration. Forty-five of the RAPD markers were mapped in the AgResearch IMF genetic linkage map, and at least one marker was located on 17 of the 26 autosomes and both sex chromosomes. Three lines of evidence were used to check for the homology of scored polymorphisms in different pedigrees, pedigree evaluation, segregation analysis, and Southern blot analysis. These results demonstrate that the RAPD assay is a powerful approach for identifying polymorphisms that can be used as markers for constructing a sheep genetic linkage map.