Debate has surrounded the use of the polygraph test in the judicial system since it was first applied. Two main issues of contention involve: (1) the methodological assumptions and scientific grounds of the polygraph test and (2) the ethical and legal issues emerging from its application in the judicial system. The current study examined the accuracy of the polygraph test in eight cases where polygraph tests were administered to individuals in Poland suspected of murdering their own children or parents. The Control Question Technique, Peak of Tension (POT), or Guilty Knowledge Test (GKT) were used; results indicated no connection between any of the eight individuals and the crimes they were suspected of committing. These findings were later confirmed by other evidence and decisions of the court; only one case remains unsolved. The polygraph chart of the eight individuals indicates that an innocent person will not necessarily react to relevant questions, as many critics charge. Thus, the methodological reservations concerning the polygraph test are unfounded. The polygraph test is a good method of verifying hypotheses concerning the guilt or innocence of individuals suspected of committing crimes. Figures, references