Polymorphism at the level of two microsatellite loci (D6S273 and TNFa) was studied in Croatian population. The most frequent alleles at D6S273 locus are D6S273 134 bp and 136 bp, while at TNFa locus two most frequent alleles are TNFa 117 bp and 99 bp. This study confirms the irregularity in distribution of microsatellite alleles in different populations with the predominance of two or three alleles on these two investigated microsatellite loci.