This paper presents Part 3 of a checklist for the taxa of bees occurring in Denmark, dealing with the families Melittidae and Megachilidae, and covering 53 species. The remaining two families (Halictidae and Apidae) will be dealt with in future papers. The following two species are hereby recorded as belonging to the Danish bee fauna: Melitta tricincta Kirby, 1802 and Hoplosmia spinulosa (Kirby, 1802). Megachile pyrenaea Pérez, 1890 and Osmia bicolor (Schrank, 1781) are excluded from the Danish checklist. Species that have the potential to occur in Denmark are discussed briefly.