Abstract The electronic structures of pyrrole and pyrrole anion have been investigated using the Pople-Segal Complete Neglect of Differential overlap self consistent field MO theory, including all valence electrons. For pyrrole the charge distribution and energy levels have been compared with those obtained from the ab initio calculations of Clementi et al. The latter calculation appears to give an excessive amount of charge migration from the H atoms, and the charge distribution obtained by the semi empirical SCF calculation is probably more realistic. In general there is reasonable agreement between the orbital energies calculated by the two methods, energy level differences being particularly well produced. For pyrrole anion comparison of charge distribution, with the obtained using Extended Hückel Theory indicates that the latter is likely to be seriously in error when used in calculations on polar molecules.