Dušan’s Code is the most important monument of Serbian medieval law. It contains a large number of provisions relating to Orthodoxy, the church, the clergy and monasticism. The first 38 articles are directly dedicated to the faith and the church. The Code also prescribes various criminal offences against Orthodoxy, and the most numerous are offences of Roman Catholic proselytism. The introductory part of the paper contains a brief analysis of the position of Roman Catholics in medieval Serbia, the relationship between Serbian rulers and popes, and especially emphasizes the role of Roman Catholic propaganda and the conversion of the Orthodox to Roman Catholicism, which was most prevalent during the reign of Tsar Dušan. The subject of the author’s legal-historical analysis is those provisions of Dušan’s Code that incriminate turning and conversion to Roman Catholicism. So far, it has been indisputably established in science that these are Articles 6, 7, 8, 9 and 21. In Article 6, the Code of Emperor Stefan Dušan proclaims: „And concerning the Latin heresy: Christians who have turned to the use of unleavened bread shall return to the Christian observance. If any fail to obey and do not return to Christian Orthodoxy, let them be punished as is written in the Code of the Holy Fathers.” Article 7 provides: „And the Great Church shall appoint head priests in all market towns to reclaim from the Latin heresy those Christians who have turned to the Latin faith, and to give them spiritual instructions, so that each one of them returns to Christianity.” Article 8 punishes the Latin priest: „And if a Latin priest is found to have converted a Christian to the Latin faith, let him be punished according to the Law of the Holy Fathers.” Article 9 prohibits mixed marriage: „And if a half-believer is found to be married to a Christian woman, let him be baptized into Christianity if he desires it. But if he refuses to be baptized, let his wife and children be taken from him, and let a part of his house be allotted to them, and let him be driven forth.” Finally, Article 21 prescribes: „And whoever shall sell a Christian into another and false faith, let him be crippled and his tongue cut out.” In the concluding remarks, the author points out the basic causes of prescribing these crimes, as well as certain historical data on Emperor Stefan Dušan’s anti-Catholic politics.