Abstract The authors describe the ultrastructural morphology of the cyst wall of sarcocysts in the muscles from Ibex, found dead and sent to this department to be examined. Several samples of the diaphragm were taken from 52 Ibex of different age and sex, one Hispanic and the others from the Gran Paradiso National Park (GPNP). The samples were prepared for electron microscopy after testing for sarcocystiosis through extemporaneous microscopic examination. Eighty-six percent were positive. The morphology of the cyst wall led to the identification of three types of sarcocysts in the Ibex of the GPNP and a further type in the Hispanic one. The morphology of the sarcocysts wall is similar to the wall of the species described in the domestic ruminants from several authors.