Messenger RNA synthesis (mRNA) accounts for a small fraction of total RNA synthesis in growing eukaryotic cells. The bulk of cellular transcription is devoted to ribosomal RNA (rRNA) synthesis (Warner, Trends Biochem Sci 24:437–440, 1999). Several unique characteristics of the rDNA and RNA polymerase I must be considered in order to accurately quantify the synthesis rate of rRNA or to characterize its processing. Indeed, an entirely different set of techniques must be applied to the study of rRNA synthesis than is routinely to study mRNA synthesis. Five of the most useful strategies for genetic and molecular analysis of rRNA synthesis and regulation are outlined in this chapter. The techniques described were developed for characterization of the model eukaryote Saccharomyces cerevisiae; however, many of these strategies can be adapted for studies in other eukaryotic cells.