Hydrogen-bonded neutral clusters of Hydrogen Peroxide, (H2O2)(n), (n = 2-4), have been theoretically investigated employing various basis-sets at the second order Moller-Plesset (MP) perturbation theory. Electron correlation effects at third and fourth order of the MP perturbation theory are also considered at MP2 geometry. Detailed analysis of many body contributions to interaction energies of dimer, trimer and tetramer is also presented. While all these H-bonded conformers emerge as closed structures, the tetramer is the only configuration that exhibits a higher molecular symmetry and is nonpolar. The ab initio results presented here can assist towards experimental identification of these clusters. (C) 2003 Elsevier Science B.V. All rights reserved.