Urban-rural differences in albedo, moisture, roughness, and thermal capacitance are often highlighted as the key causes for the urban heat island. Studies that incorporate these effects into mesoscale models of the urban atmosphere are becoming increasingly common. Anthropogenic heating is also a potential factor in the urban heat island, but is often dismissed as being relatively small in magnitude. While it is true that anthropogenic heating is small compared with summertime mid-day solar insolation, it plays a major role in the surface energy balance at times when the urban heat island effect is at its maximum (night time and winter). This paper will summarize the development and implementation of seasonal, spatially robust diurnal profiles of anthropogenic heating in mesoscale models of several cities. Observations of the urban heat island will be compared with modeled urban warming associated with anthropogenic heating (in the absence of a detailed urban canopy parameterization). Conclusions will focus on the nominal fraction of the heat island that may be explained by anthropogenic heating as well as fundamental issues regarding the appropriate implementation of such heating in mesoscale models.