Three dimensional linear structures with definite undercuts of different sizes were replicated in the first step in an elastomeric material and, in the second replication step, in a negative tone resist. Undercut masters for the first step were prepared from Si by laser ablation and anisotropic wet etching. For the second step the elastomeric replica, featuring the inverse undercut, served as a master. The first replication was performed by molding or imprinting, where the prepolymer of the elastomer was cross-linked within the master in an oven or in a thermal press, respectively. The second replication of the undercut elastomeric structures into the negative tone resist was performed successfully by molding. Comparison of the Si masters with the second replication revealed shrinkage-induced differences. Undercuts of up to 60% of the overall pattern width were successfully replicated. (c) 2007 American Vacuum Society.