An improved elastomeric mold for use in fabricating microstructures, the mold having first and second surfaces, the first surface including at least one recessed microchannel and the second surface including an access opening or filling member that extends through the mold to the first surface and communicates with the recessed microchannel. The mold is used by placing it onto a substrate with the recessed microchannel facing the substrate. The access opening of the mold is filled with a liquid material which is capable of solidifying. The access opening continuously introduces the liquid material into the space defined between the microchannel and the substrate. After the liquid material solidifies, the mold is removed from the substrate thereby leaving a microstructure formed from the solidified liquid material on the substrate.