Genetic lineage tracing is an invaluable tool to demonstrate and measure neogenesis of beta cells from putative precursor cells. Cre-Lox recombination technology can be used for indelible labeling of a cohort of cells and following the fate of these cells and their progeny in animal models. Here, the combination is described of beta-galactosidase enzymatic staining with immunohistochemical staining to demonstrate labeled cells. This technique is performed in tissue cryosections.