The paper discusses certain aspects of using decision support systems (DSS) in the anti-corruption field. In particular, it describes approaches applied by the authors to develop a DSS that helps relevant persons determine whether the situation they face constitutes a conflict of interest and choose an appropriate course of action. The proposed tool is based on the assumption that an ethically controversial situation can be conceptualized as a combination of specific elements and then compared to the attributes enshrined in the legal definition of a conflict of interest. Thus, the diversity of conflicts of interest can be reduced to combinations of a relatively small number of factors. Although this DSS was based on Russian legislation and enforcement in mind, the proposed rule-based algorithm, if properly adapted, can also be relevant for other countries.