There is a pressing need for guidelines focused on the clinical evaluation of dengue vaccines in exposed populations, because Phase 1 and 2 clinical trials of dengue vaccines have begun, and Phase 3 field trials may be warranted soon. In response to this need, the WHO Initiative for Vaccine Research (IVR) has conducted a series of expert consultations resulting in guidelines published as a WHO; 2008[Report No.: WHO/IVB/08.12]. This document, directed toward national regulatory authorities (NRAs), vaccine developers and the scientific community at large, provides guidance for the evaluation and registration of dengue vaccines in dengue-endemic countries. The new document builds on a previous guidance document published in 2002 [WHO. Guidelines for the evaluation of dengue vaccines in populations exposed to natural infection. Geneva, Switzerland: WHO; 2002 [Report No.: TDR/IVR/DEN/02.1]]. This report summarizes the recommendations in the new guidelines, which emphasize the many unique aspects of dengue vaccine trials. These include strong recommendations to collect accurate dengue incidence data across multiple transmission seasons, and to conduct Phase 2 or 3 bridging studies, post-Phase 3 follow-up safety studies and Phase 4 post-licensure trials to better elucidate vaccine immunogenicity, protective efficacy, or safety in endemic areas where multiple dengue types and other flaviviruses circulate and where flavivirus vaccines are widely used.