VANET applications can be classified into two categories: user applications and safety applications. Both of them must rely on efficient vehicular ad hoc routing protocols in order to deliver the information to the corresponding destination(s). Many possible VANET applications, e.g., accident avoidance or distributed traffic management applications, do not need explicit unicast data exchange, but locally aggregate and process the dada broadcast by other vehicles. One-to-many communications is of great importance for VANETs since vehicles are likely to exchange data by diffusion rather than in a unicast manner. Many broadcast techniques have already been proposed for MANETs, but classical MANET flooding techniques may not be suitable for VANETs and do not take advantage of the additional information available in vehicles. In this chapter we investigate various broadcast techniques that may be used in VANETs.