It has long been claimed that Contrastive Analysis (hen- ceforth CA) is able to predict (1) arrors and difficulties of learners of second or foreign languages. This claim has been verified by the fact that some of these errors and difficult es can be attributed to the interference between the learner's native language (LI) and the language being learnt (L2). This interference Is claimed to occur at the phonological, syntactic and/ or lexical levels and to be predicted by a CA of the two languages concerned (LI & L2). In order to assess this predict- ive ability one has, first of all, to understand what CA is, what results it can give and has yielded over the last two or three decades of its age and finally some notes and points of argumen- ts concerning the actual capacity and limitations of the pre- dictive power of CAs