SummaryOne of the most widely studied simple sequences in the mammalian genome is the (TG)ndinucleotide sequence. Because these microsatellites are highly polymorphic, we chose to study microsatellites from cosmids to provide genetic markers for the porcine genome. After screening a porcine cosmid library with a (CA)10probe, 20 cosmids containing microsatellites were subcloned and 17 microsatellites identified by sequencing. Oligonucleotide primers flanking the repeat were designed for seven (TG)nmicrosatellites withn>14. These seven microsatellites revealed polymorphism and were regionally assigned to chromosomes by fluorescentin situhybridization of initial cosmids. These seven loci will be useful for both the construction of the genetic map and as landmark loci on the physical map of the porcine genome.