An efficient delivery method for introducing in vitro synthesized RNA into yeast has been developed using electroporation. Spheroplast preparation, electroporation, and subsequent expression analysis can be accomplished within a single day. The use of introduced mRNA constructs avoids any complications due to nuclear regulation and is particularly suited for cytoplasmic regulatory studies. Moreover, this technique is useful for introducing those RNAs that cannot be made in vivo, such as poly(A)- mRNAs or RNAs with base modifications. We demonstrate that the Escherichia coli GUS gene and the firefly Luc gene are both excellent reporter genes for RNA electroporation.