In a photoelectron-photoion coincidence experiment on CO and CO 2, we have observed the formation and fragmentation of singly to triply charged CO2 and singly to quadruply charged CO at various energies. Doubly charged cations of both molecules are found to have unstable as well as stable states. Cations with higher charge are found to dissociate promptly. The energy dependence of the relative partial cross-sections in the energy range 125-310 eV are presented. © 2007 IOP Publishing Ltd.