Heteroepitaxial films of InSb on GaAs (100) grown by metalorganic magnetron sputtering have been studied by transmission electron microscopy. The elastic strain in the InSb films has been measured using Moire´ fringe analysis. Dilational lattice strain was found to decrease with increasing film thickness. The measured strains are in general agreement with a simple strain energy criterion for elastic accommodation. The application of a coincidence site lattice model for heteroepitaxy is also discussed.