Electrospraying in the cone-jet mode has being regarded an isothermal process, and the laws obtained under this assumption are considered valid throughout the operational range. However, self-heating due to dissipation is expected to be significant at sufficiently high electrical conductivities. This is confirmed by solving the isothermal leaky-dielectric model to evaluate the Ohmic and viscous dissipation, and estimate the temperature increase. Self-heating is important at conductivities greater than or similar to 0.05 S/m, increases rapidly at larger values, and requires the nonisothermal modeling of this regime.