Abstract: Ants are in the centre of terrestrial environment, and losing ant biodiversity would be a global ecological experimentwithout match. As genetic diversity is an integral part of biodiversity and extinction is likely to be influenced also bygenetic factors, all genetic information that can be used to illuminate their population biology is directly relevant fortheir conservation. My aim here is to review what kind of genetic information is available for evaluating the conservation status of ants and to consider what kind of information is still lacking. According to the data on endangered species,ants are just as vulnerable as any other group of organism. Some of the idiosyncrasies of social hymenopterans are likelyto expose ants to genetic and demographic threats, for instance the effective population sizes (Ne) in ants are a tiny fractionof the total numbers of ants we see. The genetic effects of polygyny and polyandry are also smaller than they seem tobe at first sight, suggesting that the number of nests is often the most important determinant of Ne. Thus, it seems thatmany ant populations have problems with respect to the "50 / 500" rule for Ne to escape extinction. Rather than the number of breeding queens, connectivity of populations seems to be decisive for the amount of genetic variation in ant populations, with small and isolated populations being depauperate of genetic diversity. Female philopatry characterizes spatialpopulation structure in many ants, causing increasing problems for colonizing new habitats and localities if habitats remain fragmented. Finally, the decreasing allelic diversity in the complementary sex determination locus is a direct threatto shrinking ant populations, because it can induce a strong inbreeding depression in the form of diploid male production.