Background. The professional occupation of a doctor quite often meets different imperfections, which have negative outcome for patients. Objective. The study was aimed to investigate the expert characteristics of improper performance of the professional duties by medical staff on the example of a particular region of Ukraine. Methods. In the study the archival materials (commission on forensic medical examinations) held in Ternopil Regional Bureau of Forensic Medical Examination in 2007-2014 years were analysed. The research results are summarized and processed with the use of general statistical methods. Results. It is defined that during this period 112 examinations concerning medical malpractice were implemented (9.05% of all commission examinations). Conclusions. Medical errors were combined, especially during the diagnostics, treatment and in medical records. The majority of cases (82.1%) of medical malpractice were caused by the objective reasons.