What is public health informatics (PHI)? Simply put, PHI is a sub-field of public health. Program faculty will journey through the evolution of public health informatics and describe how key events over the past decade have contributed to development and utilization of many computerized systems that support public health practice. Special focus will be given to major PHI applications including syndromic surveillance. Emerging (e.g., geographic information systems, text-messaging) and future (e.g., social networking, public health information exchange) PHI applications will also be discussed.