The beliefs about indicators of lying affect decision in the task of detecting lies, therefore they are important subject in forensic sciences and practice. The aim of this research was to examine accuracy and differences in the beliefs of judiciary police officers, prisoners and university students about indicators of lying. In the research participated 274 participants, from which 75 were judiciary police officers, 109 were prisoners and 90 were male students from the University in Zagreb. Research was conducted in groups among prisoners and students, while judiciary police officers completed questionnaires individually. Beliefs were measured with modified version of Scale of knowledge of indicators of lying (Vrij and Semin, 1996). The results indicated that the percetage of accuracy in identifiying indicators of lying wss low (from 30 to 32%) which was expected considering results of privious international researches. Participants' beliefs were in accordance with emotional explaination of lying and stereotypical reasoning about nervous behaviour when person is lying. The difference in the beliefs between laics and professionals was not found, although it was expected that prisoners will have the most accurate beliefs about cues of deception. .