A photoresponsive, polymeric hydrogel cantilever that deflects under illumination has been fabricated by using two-photon three-dimensional lithography. The hydrogel was prepared from a comonomer solution containing acryloylacetone, acrylamide, and N,N'-methylene bisacrylamide. The photoresponse of the cantilever was activated by photoexcitation of acetylacetone groups at 244 nm. Deflection of the cantilever by similar to45degrees was effected upon UV irradiation for 20 min.