Abstract The properties of four PbF 2 crystals of size 21 × 21 × 175 mm 3 were studied with electron and pion beams in the energy range from 1 to 6 GeV. An energy resolution for electrons of 6.3%/√ E/GeV was achieved with a 2 × 2 matrix of four PbF 2 crystals, which corresponds to 5.6%/√ E/GeV when corrected for lateral leakage by Monte Carlo simulations. The deviation from linearity was smaller than 0.5%. The time resolution was found to be better than 0.6 ns. We studied also optical properties, radiation hardness, position resolution and spatial homogeneity. An efficient separation of electromagnetic and hadronic showers was achieved.