30 K/Ar determinations are presented on 25 whole rock samples and 5 mineral concentrates from Corsican, Northern Apennines and Calabrian ophiolites. The K/Ar age of brown-green amphibole from a Corsican metagabbro is 181.4 ± 6.0 m.y. confirming that ocean crust accretion which generated the major ophiolite complexes of the Western Alpine-Apennine system has occurred since Early-Middle Jurassic time. However most datings represent isotopic re-equilibration during tectonic-metamorphic events after ophiolite generation. The Northern Apennine metabasalts and metagabbros give a Late Cretaceous age (isochron 83 m.y.) considered to be re-equilibration age of the sub-greenschist metamorphism which affected the Ligurian ophiolites during early orogenic phases. Since these tectonic-metamorphic events chronologically correspond to the HP-LT metamorphism of the Western Alps it may be argued that the Ligurian ophiolites slices were involved in the same westward (Europe-vergent) compression phases which characterized the initial stages of closure of the Western Tethyan basin. Most data on Corsican ophiolites, and possibly also those on Calabria, indicate extensive isotopic re-equilibration during Oligocene-Early Miocene times. This appears to be related to the Apennine orogeny and the back folding of the Alpine chain, in connection with the predominant tectonics characterized by eastward (Africa-vergent) thrusting.