X-Cl center dot center dot center dot H-Y interactions are analyzed by applying ab initio methods as well as the Bader theory. All calculations were performed using Pople's basis sets (6-311++G(2df, 2pd) and 6-311++G(3df, 3pd)) as well as the Dunning-type bases (aug-cc-pVDZ and aug-cc-pVTZ) within the MP2 method. For the complexes analyzed here, X-Cl and H-Y may be treated as a Lewis acid and a Lewis base, respectively. The Cl center dot center dot center dot H interactions are rather weak or at most moderate since, for the strongest interaction of the F3CCl center dot center dot center dot HLi complex, the binding energy calculated at the MP2/6-311++G(3df, 3pd) level of approximation amounts to -3.4 kcal/mol, and the H center dot center dot center dot Cl distance is equal to 2.65 angstrom, less than the corresponding sum of van der Waals radii. These interactions may be classified as halogen-hydride interactions. However, some of the complexes analyzed, especially F3SiCl center dot center dot center dot HBeF and F3SiCl center dot center dot center dot HBeF, are very weakly bound, probably by typical van der Waals interactions.