The study deals with the issue of penal reaction to violation of prohibition on entrusting an employed person with performing work in trade on Sundays and/or public holidays or performing activities related to trade in breach of that prohibition. Apart from the analysis of the statutory features of the criminal provisions in force in this respect, reference was made to the latest case law of the Supreme Court. The author shares and develops the opinion that the predominant activity, referred to in Article 6 sec. 1 point 6 of the Act on restriction of trade on Sundays and public holidays, constitutes an activity that covers the assortment indicated in this provision. The Author also supports the opinion that is the formal nature of the entry in the relevant register which designates such activities.