Leftover uncured polydimethylsiloxane (PDMS) polymer is generally discarded. In an effort to minimize this waste, we have developed a method for cryo-preserving PDMS prepolymer involving a simple storage technique for the preservation and repeated use over 1 month. Aliquots of the uncured PDMS prepolymer were stored at −20 or −80°C, then conveniently and easily thawed at body temperature (37°C). Proposed cryo-preservation was successfully evaluated using diverse biological and physical tests. This method of cryo-preserving PDMS reduces both the material waste and labor of soft lithography process and may enable soft lithography to be environmentally friendly relative to previous methods. The method may be popularly accepted for application to a variety of common microdevice fabrication procedures. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40378.