Polyacrylamide gel electrophoresis (PAGE) constitutes a powerful technique for the efficient purification of RNA molecules dedicated to applications that require high purity levels. PAGE allows for the fractionation of RNA obtained from cell extracts, chemical or enzymatic synthesis, or modification experiments. Native or denaturing conditions can be chosen for analytical or preparative-scale separations and the nucleotide resolution can be tuned by changing the percentage and reticulation of the gel material. In this protocol, we focus on the preparation of milligram-scale amounts of ~200 nucleotides (nt) RNA molecules that were used in subsequent crystallization experiments.