Islet transplantation is a safe and effective procedure; however, it depends on the critical step of isolating high quality of islets from whole pancreas. Human islet isolation requires considerable experience and expertise, and is frequently seen as ‘an art rather than a science’. However, without scientific knowledge of pancreatic anatomy, real experience can not be gained. In particular, an understanding ductal anatomy is important to perform human islet isolation. This review is based on clinical experience of more than 900 human islet isolations performed over 10 years and aims to highlight pancreatic anatomy and surgical techniques in islet processing.