The potential energy surfaces (PESs) associated with the reactions between ethylene and N+(P-3,D-1) ions have been investigated through the use of high-level G2(MP2) ab initio calculations. Although the N+(P-3) + C2H4 entrance channel lies 46.7 kcal mol(-1) below the N+(D-1) + C2H4, most of the singlet-state cations are more stable than their triplet-state counterparts because, in general, the bonds in the former are stronger than those in the latter, favoring the crossover between both PESs. Several minimum energy crossing points between both hypersurfaces have been located, and the corresponding spin-orbit couplings indicate that spin-forbidden processes in N+ + C2H4 reactions cannot be discarded. According to our survey, the product distribution in both N+(P-3) + C2H4 and N+(D-1) + C2H4 reactions should be quite different. While for the triplets the CNH+, agreement with the available experimental HCNH+, HCCH2+ and HCCH+ product ions should be observed, in, information, for the singlets the formation of CH3+ should be the dominant process.