Leaf rust caused by Puccinia triticina is a major disease of durum wheat in the Mediterranean region. This pathogen has a complex life cycle. It alternates between wheat and the secondary host, Anchusa italica. The latter was found to be functional in Morocco. The populations of the pathogen, alternating on Anchusa italica, belong to a separate compatibility group than those alternating on Thalictrum speciosissimum in the temperate areas. The virulence spectrum of the leaf rust population alternating on Anchusa italica is diverse with the dominance of a pathotype avirulent on most of the Lr genes. Although many sources of resistance to leaf rust are identified among durum wheat cultivars, very little is known about the inheritance and the expression of resistance in this host species. The available studies on the expression of resistance to leaf rust in durum wheat indicate a recessive type of resistance in most cases.