The recent publications by Rezania et al. and Pagliuca et al. describe culture methods for the generation of maturing pancreatic beta cells. These maturing beta cells express insulin and are able to secrete it in a glucose-dependent manner, although with altered secretion kinetics. The cells generated at the end of these two published protocols are both derived from stage 4 PDX-1+/NKX6.1+ pancreatic progenitor cells, which are similar to those generated using the STEMdiff Pancreatic Progenitor Kit. It is important to note that the cells generated at the end of the 4-stage protocol that accompanies the STEMdiff Pancreatic Progenitor Kit are truly pancreatic progenitor cells in that they retain the ability to generate both endocrine and exocrine cell lineages under appropriate conditions. Since the kit contains multiple basal media and supplements to support the different differentiation stages, it is also possible to isolate cells from earlier stages, thus allowing the user to study the development of pancreatic cell types from earlier precursors.