A sharp-cut cyclone with an aerodynamic cut-off diameter of 1 μm, when operated at a flow rate of 1 L min⁻¹, was built by 3D-printing and tested against a metallic (aluminum) counterpart having the same design and dimensions. The penetration efficiency of both cyclones was experimentally determined using quasi-monodisperse aerosol particles having aerodynamic diameters from ca. 100 nm to 2 μm. The aerodynamic cut-off diameter for both cyclones was very similar and in accordance with the expected design value. The penetration efficiency curve of the 3D-printed cyclone was less steep compared to that of its metallic counterpart. This difference is most likely attributed to the higher surface roughness of the inner parts of the 3D-printed cyclone - as also indicated by the greater pressure drop it exhibits compared to the aluminum cyclone when operated at the same flow rate - and not by higher deviations from its design dimensions resulting from the tolerances of the 3D printer. Despite that, the substantially low cost, speed, and ease of manufacturing, make the 3D-printed cyclone a highly promising solution for applications in aerosol metrology.