Seven Portuguese dog breeds (n = 344) and Iberian wolves (n = 44) were analysed using a previously characterized set of 9 autosomal STRs. The total dataset was used to estimate genetic diversity and parameters of forensic interest among and within populations. Clustering analyses were performed to investigate the genetic similarity of individuals belonging to the same morphological population. Dog breeds showed relatively heterogeneous genetic constitutions and individual dogs could not be readily assigned to their breeds of origin on the basis of these genotypes alone. Nevertheless, genetic discrimination between wolves and dogs was possible with a high probability (>98%) of correct assignment of each individual to its population of origin.