Osmia mutensis is only known from the female holotype. Female O. mutensis are black bees with a greenish metallic hue, which is most noticeable when looking laterally at the bee. O. mutensis has whitish-yellow hair on the head, thorax, and abdomen, with dark hair interspersed on the frons and vertex (Peters 1978). Female body length is approximately 13 mm (Peters 1978). Male of O. mutensis is unknown.
O. mutensis females are similar to O. kohlii and O. fedtschenkoi in the shape of the mandibles, which lack a cutting edge between the two inner teeth. O. mutensis can be easily differentiated from these species by the simple, straight apical edge of their clypeus (Peters 1978).
Osmia mutensis is known only from western Turkey (Özbek 2013).