For several years now, with the introduction of the health care sector reform we have been observing a considerable drop in the number of postmortem examinations performed in patients who died in hospitals. The decrease amounts to as much as 50 to 70%. This is undoubtedly a consequence of financial restrictions imposed on the management of these inpatient facilities. On the other hand, Departments of Forensic Medicine established to evaluate the so-called medical errors are swamped with an increasing avalanche of complaints concerning the appropriateness of therapeutic management. This leads to a growing number of orders from penal prosecution and jurisdiction agencies with requests for assessment whether a medical error has been committed in a particular case. The result of a postmortem examination is practically the only basis for a factual evaluation of a given case. When no autopsy has been performed, the experts are virtually helpless, and in the majority of such instances, they are forced to refuse passing an expert opinion. The report presents basic principles of medico-legal opinionating in criminal cases (including proceedings pertaining to medical errors), the rules governing the medical error assessment, as well as problems encountered in evaluating the appropriate course of treatment when a post mortem examination has been waived.