The Gsearch system allows the selection of sentences by syntactic criteria from text corpora, even when these corpora contain no prior syntactic markup. This is achieved by means of a fast chart parser, which takes as input a grammar and a search expression specified by the user. Gsearch features a modular architecture that can be extended straightforwardly to give access to new corpora. The Gsearch architecture also allows interfacing with external linguistic resources (such as taggers and lexical databases). Gsearch can be used with graphical tools for visualizing the results of a query.