The development of inexpensive and effective approaches to transiently decrease gene expression in vivo would be useful for the study of physiological processes in living animals. DNAzymes are a novel class of DNA oligonucleotides that can catalytically cleave target mRNAs and thereby reduce protein production. However, current methods for their delivery in vivo are limited and inefficient. In this study, we show that electroporation can be used to deliver DNAzymes to the intact mesenteric vasculature of rats. Using PKC as a target, a set of wild type and mutant control DNAzymes were designed and shown to reduce both PKC mRNA and protein levels in cultured smooth muscle cells in a specific manner. The wild type DNAzyme reduced PKC protein levels by 70% at 24 hours in two different cell lines without decreasing the levels of 5 other PKC isoforms that were tested. When delivered to the intact vasculature using electroporation, the DNAzyme reduced PKC protein levels by greater than 60% without affecting these other PKC isoforms. Electroporation was required for oligonucleotide transfer and was able to deliver the DNAzymes to multiple cell layers in the vessel wall. Protein levels were reduced maximally by 24 hours post-electroporation and returned to normal by 48 hours. These results suggest that electroporation can be used to deliver DNAzymes and other DNA oligonucleotides to the vasculature in vivo and can decrease gene expression for a window of time that can be used for experimental studies.