In this article, we study an anisotropic rotating system arising in magnetohydrodynamics (MHD) in the whole space R 3 , in the case where there are no diffusivity in the vertical direction and a vanishing diffusivity in the horizontal direction (when the rotation goes to infinity). We first prove the local existence and uniqueness of a strong solution and then, using Strichartz-type estimates, we prove that this solution exists globally in time for large initial data, when the rotation is fast enough.1991 Mathematics Subject Classification. 76D03; 76D05; 76U05, 76W05.