Pancreatic ductal carcinoma remains the 4th leading cause of cancer death in both men and women in the United States, with an overall 5-year survival of less than 3%. Over the last decade, significant advances have been made in our understanding of the molecular biology of pancreatic ductal carcinoma, with pancreatic cancer now considered one of the better characterized neoplasms at the genetic level. The advances in the understanding of the molecular genetics of pancreatic cancer initially focused on events that occur in the development and early genetic progression of the disease. This progression has been associated with the accumulation of multiple genetic alterations in various cancer-causing genes, leading to the development of a histological and genetic progression model. In the model, pancreatic cancer develops from non-invasive intraepithelial precursor lesions termed pancreatic intraepithelial neoplasias, with each progressive stage associated with accumulated mutations in oncogenes, tumor-suppressor genes, and mismatch repair genes. Other aspects of the development of pancreatic ductal carcinoma, such as tumor invasion, tumor-stromal interaction, metastasis, and chemotherapeutic resistance are more poorly understood. Recent studies utilizing global gene expression methodologies have provided insight into some of these processes and have allowed for the development of potential tumor markers which could be used for early detection and diagnosis of this difficult disease. In order to improve the survival of patients with pancreatic carcinoma, we need to better understand the fundamental changes that occur in pancreatic ductal carcinoma. The following article reviews the genetic mutations and syndromes known to be associated with pancreatic ductal carcinoma as well as recent advances in the study of global gene expression.