A taxonomic revision of the lichenized species of the genus Omphalina in the Iberian Peninsula is presented, based upon fungal and lichen herbarium material, as well as on fresh collections. Relevant morphological and ecological features are discussed and a diagnostic key is provided. Four lichenized species, O. ericetorum, O. hudsoniana, O. meridionalis and O. velutina are recognized. A squamulose vegetative thallus (Coriscium-type) is present only in O. hudsoniana, while the other three species form a thallus of hyphal globules (Botrydina-type). Anatomical features of the vegetative thallus cannot be used to distinguish between these last three species. Whilst O. hudsoniana is known only from the montane belt of the Eurosiberian Region and O. meridionalis seems to restricted to the Mediterranean Region, living in more or less humid sites of the Supramediterranean belt, the other two species, O. ericetorum and O. velutina, are widespread.