The addition of water to petroleum-derived fuels has been an area of intense research for many years as an alternative to reduce emissions produced by fuel combustion (NOx, smoke, etc.). Additionally, some improvement in fuel consumption has been observed when using fuel emulsions. The handling of heavy and very viscous crude and refined oils has been improved when using emulsions. The present work comprises the results which have been accumulated for the utilization and studies of the pyrolysis products as tensioactive agents for preparation of watery emulsions of crude and distillated fractions from the petroleum. The behavior of the inverse and direct emulsions prepared with pyrolysis product emulsifier agents and studies about the inversion of one into another for adjustment of the handling and combustion of heavy and viscous petroleum products are discussed. Characterization of the emulsifier agent compositions and their effects on the superficial and interfacial tensions, the emulsion rheology, combustion particularities, and other aspects are presented. The results of the Group of Emulsion at the University of Oriente regarding the watery fuel emulsion applications in different combustion systems and other uses are presented as well.