Leoville is a CV3 chondrite that contains a large variety of inclusions. Besides refractory inclusions resembling those in Allende, fine-grained, dark inclusions are especially prominent. Some of these are xenoliths of material very similar to CM chondrites in texture, bulk composition, and oxygen isotopes. However, they show an unusually large range in the degree of hydrous alteration. Other dark inclusions are similar to host matrix. The CV3 host of this breccia is similar to other CV chondrites, although less metamorphosed than Allende. We suggest that Leoville is a typical accretionary breccia whose parent body accreted after the CM-like material represented by the xenoliths had formed and undergone alteration. After accretion Leoville suffered severe deformation, leading to foliation stronger than in any other chondrite, but the nature of the event that caused this remains unclear.