The electronic structure of cobalt phthalocyanine (CoPc) monolayer is investigated by means of the first-principles all-electron full-potential linearized augmented plane wave energy band method. The magnetic properties of the CoPc monolayer are studied with spin polarised calculations. It was found that Co atom has magnetic moment of 1.01 mu(B). Charge transfer between the CoPc ligand pi and metal atom d orbitals causes a weak polarisation of nitrogen atoms within the molecule inner ring. The electronic properties of Co atom are essential in shaping the ground state electronic structure of the CoPc monolayer near the Fermi level. The calculated values of work function and ionisation potential of the model monolayer are 5.01 and 6.46 eV, respectively. (c) 2006 Elsevier B.V. All rights reserved.