The geometrical structure, binding energy, and vibrational spectra of small clusters of HOCl and water molecules, HOCl(H2O)(n), n = 1-4, have been investigated at the MP2 revel of theory, using triple-Z, 6-311++G(d,p), basis sets. The ab initio results predict for the clusters an almost planar ring skeleton, made up of the O atoms and one H atom from each molecule, linked by hydrogen bonding to the next oxygen. The species with one water unit presents two almost equally stable conformers, syn and anti, in agreement with previous calculations. Two stable structures have also been found for clusters with three and four molecules of water, one where the H atom of the HOCl molecule makes part of the ring, and another one in which the Cl atom is in the ring. The more stable in either case is found to be the H-in molecule, with a difference of 35.6 kJ/mol in optimized energy. The predicted spectra for these two species are very different. As the number of water units increases, the corresponding clusters become more stable, and a number of physical effects is predicted. The more important one is the increase in the intramolecular O-H bond length, which is responsible for a large reduction in the wavenumber of the corresponding O-H vibration. The results indicate the formation of hydrogen bonds and a partial proton transfer from HOCl to the water ring structure. In a parallel calculation, water clusters, (H2O)(n), n = 1-5, have also been investigated. Our results agree well with those of previous authors.