The spin-rovibronic spectrum of the (A) over tilde (2)Pi <-- (X) over tilde (2) Sigma(+) electronic transition of MgNC has been determined variationally by RVIB3 [Mol. Phys. 98 (2000) 1697], based on the three-dimensional near-equilibrium potential energy surfaces of the 1(2)A ', 2(2)A' and 1(2) A" states together with the transition moment functions between these electronic states. The theoretically determined spectrum is shown to be in very good agreement with the corresponding gas-phase high-resolution experimental spectrum. (C) 2003 Elsevier B.V. All rights reserved.