Genetic data are becomming increasingly important in ecological studies. I will present a method for estimating animal abundance based on DNA-fingerprints from a random sample of individuals. The underlying idea is that DNA-fingerprints provide information about biological relationship, and that the degree of relationship between individuals is related to the population size. The estimation criterion used is a pseudo-likelihood based on pairwise comparisons of individuals. Simulation experiments will be presented, showing what sample sizes are required, and how many genetic markers are needed, in order for the method to be useful in practice.