In Argentina the best and most complete marine Jurassic succession is exposed between 32° and 39° S, along a N-S belt roughly coincident with the border with Chile. Here all stages, except the Kimmeridgian, are represented by marine facies. Ammonites have provided a biostratigraphic framework to date and correlate lithostratigraphic units and sequences, to reconstruct the history of the marine fill, and allow the development of other palaeontological and geological studies. Recent studies on the systematics and/or biostratigraphy of Andean ammonites have provided the basis for the presentation of a summary of the 45 ammonite zones of the Jurassic of west-central Argentina and to stress its significance in reconstructing the palaeogeographic evolution of that region.