The category of cpos from a synthetic viewpoint Marcelo Fiore Giuseppe Rosolini LFCS, University of Edinburgh Dipartimento di Matematica The King's Buildings via Dodecaneso 35 Edinburgh EH9 3JZ, Scotland 16146 Genova, Italy Abstract We provide an internal characterization of the category w-Cpo of w-complete posets and w-continuous functions within the model H of SDT recently introduced by the authors. It follows that w-cpos lie between the two extreme synthetic notions of domain given by repleteness and well-completeness.