Pure rotational spectra of five isotopomers of the 1:1 weakly bound complex formed between carbonyl sulfide and trifluoromethane (TFM) have been measured using Fourier transform microwave spectroscopy. The experimental rotational constants and dipole moment components are consistent with a structure of C-s symmetry in which the dipole moment vectors of OCS and HCF3 are aligned antiparallel and at an angle of about 40 degrees and with a center of mass separation of 3.965(26) angstrom. The derived H center dot center dot center dot O distance is 2.90(5) angstrom, which is up to 0.6 angstrom longer than is seen in other similar TFM complexes exhibiting C-H center dot center dot center dot O interactions. Ab initio calculations at the MP2/6-311++G(2d,2p) level give a structure with rotational constants that are in reasonable agreement with those of the normal isotopic species.