The spectroscopic properties of I-2-Rg (Rg = He, Ne, Ar) van der Waals complexes have been studied in detail using ab initio MP2 and CCSD(T) methods in conjunction with the correlation consistent quadruple-zeta quality basis sets. The dissociation energy and depth of the potential well have been calculated using potential method and supermolecular approach in order to remove the discrepancy among the existing theoretical and experimental values. Most of the spectroscopic properties are first reported and the rest agree very well with the theoretical and experimental values wherever available. (C) 2011 Elsevier B.V. All rights reserved.