Potential energy curves for the lowest (3)Sigma(-) (3)Pi, (1)Delta, and (5)Sigma(-) states of NaN have been calculated by the multireference singles and doubles configuration interaction method, including Davidson's correction for quadruple excitations (MR-SDCI(+Q). It is shown that the former three are bound states, while the last one has no minimum. The ground state of NaN is predicted to be (3)Sigma(-) for which the binding energy is evaluated as 0.859 eV, and the rotational constants are calculated as B-e = 11.632 and B-0 = 11.558 GHz. The spectroscopic constants presented here will help in the detection of NaN in interstellar space. (c) 2006 Elsevier B.V. All rights reserved.