The existing sketch recognizers perform only a limited drawing recognition since they process simple sketches, or rely on drawing style assumptions that reduce the recognition complexity, and in most cases they require a substantial amount of training data. In this paper we present a parsing strategy for the recognition of hand-drawn diagrams that can be used in interactive sketch interfaces. The approach is based on a grammar formalism, namely Sketch Grammars (SkGs), for describing both the symbols? shape and the syntax of diagrammatic notations, and from which recognizers are automatically generated. The recognition system was evaluated in the domain of UML use case diagrams and the results highlight the recognition accuracy improvements produced by the use of context in the disambiguation process.