In hot star atmospheres, the Stark broadening mechanism is the main pressure broadening mechanism. An interesting application where such a mechanism is of interest is the modeling and investigation of hot star spectra, stellar atmospheres and subphotospheric layers. Consequently, for the investigation and modeling of the Hg-Mn star and other type of hot star atmospheres, the Stark broadening parameters for Co III spectral lines may be of interest. Here we present Stark broadening data for 20 Co III spectral lines (from a^6^D-z^6^D^o^ and a^6^D-z^6^F^o^ Co III multiplets), as a function of temperature, calculated by using the modified semi-empirical approach. The importance of the electron-impact effect in the case of the Co III 194.98nm line for several stellar atmosphere models has been tested.