Two thousand nine hundred and thirty-one tri- and tetranucleotide short tandem repeat polymorphisms (STRPs) developed by the Cooperative Human Linkage Center were assigned to chromosomes using the NIGMS somatic cell hybrid mapping panel 2 and an efficient pooling strategy. Approximately 82% of all STRPs tested were assigned by this method, with 96.7% accuracy. Many of the single chromosome cell lines contained portions of additional chromosomes, confirming previous reports. The cell lines for chromosomes 6, 14, and 20 contained extensive portions of other chromosomes. Five previously unreported chromosomal contaminants were identified and are reported. A new pooling strategy was designed to minimize ambiguous assignments.