A growth factor-mediated selection method was used to obtained insulin-secreting cells from human embryonic stem cells (hESC; Royan H1). Our resultant cells were positive for dithizone, a zinc-chelating agent known to selectively stain pancreatic beta cells and immunoreactive for antibodies against insulin, glucagon, and C-peptide. Semi-quantitative reverse transcription-polymerase chain reaction detected expression of proinsulin, insulin and other pancreatic beta-cell-related genes, such as Nkx6.1, Is11, Glut2, Pax4, and prohormone convertase2 (PC2). Moreover, glucagon, somatostatin, K(ATP)-channel genes KIR6.2 and SUR1, islet amyloid polypeptide (IAPP), PC1/3, and glucokinase (GCK) were expressed in the differentiating hESC in a developmental stage-dependent manner. Also, the addition of glucose to the culture medium triggered insulin release from differentiated cells, but transmission electron microscopy of the differentiated cells did not show typical beta-cell granules, even though secretary granules were detected. The results showed that hESC have the ability to transcribe and process insulin, but further improvements of the current method are required to generate a sufficient source of true beta cells for the treatment of diabetes mellitus.