A new colony of a single segregating inbred strain of the Syrian hamster (Mesocricetus auratus), designated KVL, has recently been developed at the Royal Veterinary and Agricultural University, Copenhagen, Denmark. The segregation occurs with respect to coat colour (pied gray/pied brown) as a result of inbreeding with forced heterozygosity. After 20 generations average litter size was 6.7 at birth and 5.57 at weaning. Mean generation interval was 89.4 days. An initially significant decrease in productivity (inbreeding depression) levelled out with further generations and has now stabilized. The colony is being maintained.