The present article comprises a theoretical study of structures and energetics of the lowest energy conformers of peroxyformic acid (PFA) and its hydrated variants, viz. PFA center dot center dot center dot(H2O)(n) (n=1-4), at the molecular level. We have employed two different ab initio quantum chemical methods, viz. restricted Hartree-Fock (RHF) and the second-order Mlller-Plesset (MP2) perturbation theory with the basis sets 6-31G(d, p) and 6-311++G-(2d, 2p). Modifications in the structure as well as vibrational frequencies of PFA brought about by successive addition of H2O molecules are also discussed. Cooperativity of hydrogen bonding in these clusters can be gauged through a detailed many body interaction energy analysis.