This investigation presents the retrospective evaluation of paternity testing done as a "second opinion" in the last four years at the Institutes of Legal Medicine in Jena, Greifswald, and Kiel (Germany). All analyses were court-ordered and were preceded by paternity tests of "private" labs. The cases were selected in chronological order without any further exclusion criteria. A total of 59 cases, in which "private" laboratories from all regions of Germany had already performed paternity tests, were evaluated. In all cases, analyses were mainly done by PCR-based STR-typing (8 - 20 STRs). 18 % of the investigated "private" expert opinions showed a false determination of alleles. In two cases, paternity was wrongly confirmed or excluded. The reasons for the mistakes of private laboratories were hard to analyse, since most labs did not provide sufficient information (e.g. alleles, kits and chemicals used) in the written test results. In several cases, not even the typing results were revealed. Furthermore, in paternity testing of "private" labs the identity of the persons examined was usually not assured (e. g. by photo documentation or fingerprints) adding to the problem of insufficient test result reliability.