The study presents the research potential of a criminal record system that often appears abroad in the criminal psychology literature. The study undertakes to explore the possibilities of the Hungarian Modus Operandi Register that can be used in research, with a special focus on what data are available and how their analysis could contribute to the development of criminal profiling. Foreign examples show that research in the Modus Operandi Register has yielded important results in identifying types of homicides and preventing victimization of sexual offenses, as well as in sexual homicides against children. The article processed domestic and foreign literature and research results. The main consideration was to summarize the results obtained using the data from the Modus Operandi Register. Modus Operandi can indeed be a research treasure trove if access to data – in compliance with the legal framework – allows researchers to carry out analyses, and if the incorporation of their findings is encouraged by the law enforcement officials. Another area of research could be to analyse patterns of criminal careers, as well as to examine what kind of criminal diversity can be discovered for each offender and how this affects his or her methods. Finally, it could be examined to what extent the trends that can be discovered in international research appear among Hungarian criminals. These approaches may contribute to a more efficient operation of the police.