The HeH2 van der Waals complex has been identified in a molecular beam produced by a cryogenic (T-0=24.7 K) free jet expansion of a 1% H-2 mixture in 99% He-4 gas. The weakly bound HeH2 complexes in the beam are identified via their first order diffraction angles after passing through a 100 nm period transmission grating. An electron impact mass spectrometer analysis of the diffraction patterns is used to discriminate against ion fragments of the constituent gas clusters. (C) 2004 American Institute of Physics.