We have recently developed a biochemical approach to isolate miRNA-bound mRNAs and have used this method to identify the genome-wide mRNAs regulated by the tumor suppressor miRNA miR-34a. This method involves transfection of cells with biotinylated miRNA mimics, streptavidin pulldown, RNA isolation, and qRT-PCR. The protocol in this chapter describes these steps and the issues that should be considered while designing such pulldown experiments.