Herein, we describe a simple and general multi-component synthesis of 5-arylselanyluracils by the regioselective C–H selenation of uracils. Reactions of uracils with arylboronic acid and Se powder in the presence of AgNO₃ (10 mol%) at 120 °C under aerobic conditions afforded various 5-arylselanyluracils. The source of the introduced selanyl group was prepared from a commercially available arylboronic acid and Se powder in the reaction system, thereby ensuring a simple and efficient protocol. This reaction represents the first example of the synthesis of a 5-arylselanyluracil in a multi-component system.