Ion-pair formation processes of N2O are studied in detail using synchrotron radiation in the 24-34 eV photon energy range. Positive ion-negative ion coincidence (PINICO) spectroscopy makes it possible to distinguish dissociation into three bodies, O-+N++N, from dissociation into two bodies, O-+N-2(+). The photodissociation efficiency curves for the two processes are measured. Several resonance-like peaks in the curves are assigned to doubly excited Rydberg states of N2O from an analysis of kinetic energy release in dissociation.