An estimate is obtained for the cross section for rotational relaxation from a small subset of |J,K〉 states in the 52302 vibrational level of S0 p-difluorobenzene. The method of stimulated emission pumping (SEP) is used to prepare the initial |v,J,K〉 population. Collisional relaxation induced by the bath of p-difluorobenzene molecules in Boltzmann equilibrium is monitored from the intensity of wavelength-resolved single vibronic level fluorescence generated via selective excitation from the SEP-prepared levels. The average efficiency for rotational relaxation σ/σHS, relative to the hard-sphere cross section σHS, is found to be 5 ± 2 for ground-state p-difluorobenzene. This study demonstrates that rotational relaxation in a nonpolar polyatomic molecule in its S0 state is as efficient as that found for similar polyatomics in their S1 electronic states.