This is a protocol for performing RNAscope® in situ hybridization analysis on fixed-frozen mouse brain tissue using the RNAscope® Multiplex Fluorescent v2 kit (Advanced Cell Diagnostics; ACD). It is similar to the v2 protocol provided by ACD; places where it deviates from ACD's protocol have been indicated. This protocol provides steps for staining sections through dorsal striatum of mouse brain, but can also be applied to other brain areas. It also has steps for sample preparation, including cryosectioning.