The pressure-induced metallization of BaSe has been observed using both electrical-resistivity and optical-reflectivity measurements. Measurements of the electrical resistivity of BaSe up to a pressure of 65.2 GPa show a leveling off of the resistivity at about 52 GPa, indicating the metallization of BaSe. Optical reflectivity spectra taken of the BaSe-samplediamond interface up to 72.2 GPa show a significant rise in the low-energy (0.5 eV) reflectivity at pressures above 61 GPa. We interpret this rise in reflectivity to be associated with the plasma edge of BaSe in its metallic state. The resistivity and reflectivity data are compared with each other as well as with published high-pressure optical-absorption data. © 1987 The American Physical Society.