Within the framework of density functional theory, we have studied the electronic ground-state properties and approximated the optical dielectric constants and reflectivity of PbWO4. The reflectivity calculated from the single-particle band structure co mpares with the experimental reflectivity unexpectedly well, including the sharp peak at the absorption threshold. This suggests that the exciton binding energy for PbWO4 may be small, possibly ~ 0.1 eV, based on data to be discussed.