A method of forming a microneedle device comprises the steps of coating the front and back surfaces of a substrate with a protective masking material, patterning the protective masking material to form a protective mask on the front surface of the substrate and an opening in the protective masking material on the back surface of the substrate, and simultaneously wet-etching both front and back surfaces of the substrate to provide a generally conical microneedle on the front surface of the substrate and a generally conical pit on the back surface of the substrate. The dimensions and location of the protective mask and opening are chosen so that the pyramidal pit extends from the back surface to intersect the front surface of the substrate, generally on, or adjacent to, a surface of the conical microneedle. Thus, a through-hole is formed in the substrate providing fluid communication from a rear of the substrate to a location on the front surface of the substrate, either on the microneedle surface or adjacent to a base of the microneedle.