The PrO 2 dioxide is an insulator with band gap of 6eV. The 4f 1 ground state configuration of Pr 4+ in cubic symmetry sites is subjected to a strong crystal field (CF) interaction. The available inelastic neutron-scattering data show that the CF ground state, Γ 8 , and the excited state Γ 7 are separated by 130meV. This energy separation is described by a single CF parameter A40〈r4〉=-661K. The standard local density approximation (LDA) gives the gap value of 3.7eV and the CF parameter A40〈r4〉=-59K. The LDA+U-based approach, where the Coulomb correlations inside the Pr-5d and O-2p states is described using the parameters U=0.5Ry and J=0.1Ry, results in the band gap value of 6eV and A40〈r4〉=-107K.