Presheaf models [Osius, 1975, Fourman and Scott, 1979, Moerdijk and Mac Lane, 1992] are a simple generalization of Kripke models and provide one of the most natural semantics for intuitionistic predicate logic. Although a completeness result for this semantics is known, this is usually obtained either non-constructively, by defi ning a canonical Kripke model,or indirectly, e.g. via categorical equivalences with omega-models as in [Troelstra and Van Dalen, 1988]. This paper describes an elementary canonicalmodel construction by means of which completeness is established in a perspicuous, direct and constructive way.