Big BaF 2 crystals of 1-2 1 volume and up to 15 cm thickness were investigated with respect to their application as gamma-ray detectors. In particular, we were interested in the light transmission in the UV region, and the energy and time resolution. We found that an energy resolution of ∼ 12% (662 keV) and a time resolution of ∼ 0.4 ns ( 60Co, 300 keV threshold) can be obtained simultaneously. For these features, BaF 2 is superior to NaI or BGO in cases where good timing is essential. Gamma-rays and alpha particles can be clearly discriminated; as for the latter the fast component does not show up in the scintillation light.