The scintillation efficiency of a benzene + p-terphenyl solution, extrapolated to unit energy transfer efficiency, has been determined to be 0.042 (or equivalently 0.0116 ± .004 photon/ev). This corresponds to a G value for production of1B2ubenzene of 1.55 ± .05. It is suggested that the difference between this value and that for other alkyl benzene liquids (1.9–2.5) and for anthracene crystal (2.20) is related to the efficiency with which upper states of these substances make internal conversion to the emitting or transferring state.