In this article we present the results of spin-polarized band-structure calculations on the ordered binary compounds of Co-Pt. Comparison is made with experimental values for the magnetic moments. The results of our calculations show a non-local magnetic moment behaviour in these systems. Furthermore we find an almost constant number of holes in the Pt 5d band for the different compounds. The nature of the magnetic interactions is investigated. The coupling between the Co atoms can be described with the Heisenberg Hamiltonian and the exchange coupling parameters are evaluated. With these exchange parameters we are able to calculate the Curie temperature of ordered and disordered Co-Pt alloys.