Among a large number of expert opinions concerning disputed paternity cases prepared in the Chair of Forensic Medicine and Medico-Legal Toxicology, Silesian University of Medicine, Katowice, there were those in which the use of a standard 15 autosomal loci AmpFISTR Identifiler kit was not sufficient to give an unequivocal opinion. The authors report a case of disputed paternity, in which the analysis done by applying an AmpFISTR Identifiler kit showed no paternity heredity in 2 loci in the child. As allele distribution did not exclude mutation, further genetic markers were determined using PowerPlex ESX and FFFL kits and further three exclusions were found. Moreover, X-chromosome loci were determined using a MentypeAngusX8 test, which confirmed the exclusion of paternity in further 4 loci.