Five distinct species of OCS-hydrogen van der Waals complexes (OCS-orthoH(2),-paraH(2),-paraD(2),-orthoD(2), and -HD) have been observed by infrared spectroscopy in the region of the OCS nu (1) vibration (approximate to 2062 cm(-1)) in a pulsed supersonic jet expansion using a tunable diode laser probe. The spectra are those of prolate asymmetric rotors, with observed a-type transitions (DeltaK=0), but no b-type transitions (DeltaK=+/-1). The fitted rotational parameters are consistent with structures having intermolecular separations in the range of 3.6-3.8 Angstrom and angles of about 70 degrees between the OCS axis and the hydrogen center of mass. The band origins are slightly red-shifted (-0.05 to -0.20 cm(-1)) relative to that of the free OCS molecule. The results are of interest due to recent observations of the same complexes trapped in ultracold helium droplets; there is a remarkably close correspondence of the vibrational band origins of the free and trapped species.