Stark broadening parameters, widths and shifts, for 84 spectral lines of doubly-ionized cadmium (Cd III) have been calculated using the modified semi-empirical approach (MSE). Calculated spectral lines belong to the transitions 4d^9^5s-4d^9^5p and 4d^9^5p-4d^9^5d. Widths and shifts of the spectral lines are given for temperature range of 5000K-60000K and an electron density of 10^23^m^-3^. The influence of collisions with charged particles on Cd III UV stellar lines along the HR diagram is discussed. Compared to the Doppler broadening, the influence of the Stark broadening mechanism is more important for deeper atmospheric layers and for larger values of logg. Stark broadening does not depend on turbulent velocity for the considered stellar model of a standard main sequence hot star of A0 spectral type. The influence of the Stark widths for standard models of DA and DB white dwarfs is also discussed.