The invention relates to a method of identifying, obtaining and/or quantifying a culture of pancreatic cells selected from the group consisting of ductal/endocrine progenitor cells, endocrine progenitor cells, early endocrine cells, and fully differentiated endocrine cells. Also contemplated is a method of expanding the numbers of such cells as well as sorting such cells. The invention further relates to a selective cell surface marker, DDR1, that permits the selection of a unique subset of cells with pancreatic endocrine progenitor phenotype. Furthermore, the invention relates to isolated cells selected from such cells and compositions thereof.