Corpora have been used for pedagogical purposes for more than two decades but empirical studies are relatively rare, particularly in the context of grammar teaching. The present study focuses on students' attitudes towards grammar and how these attitudes are affected by the introduction of concordancing. The principal aims of the project were to increase the students' motivation by showing them that English grammar is more than a set of rules in a book and to enable them to assume more responsibility for their own learning. The idea was to introduce the use of language corpora into the curriculum for first-semester English at Växjö University in Sweden, as a complement to grammar textbooks and ordinary exercise materials. Between classes, the students worked with problem-solving assignments that involved formulating their own grammar rules based on the examples they found in the corpus. In the classroom, a system of peer teaching was applied, where the students took turns at explaining grammatical rules to each other. Besides presenting a new way of working with grammar, we also provided the students with a tool for checking questions of usage when writing English texts in the future, since the corpus we use is free of charge and available to all. The work with corpora and peer teaching was evaluated by means of questionnaires and interviews. This article describes and evaluates this initiative and presents insights gained in the process. One important conclusion is that using corpora with students requires a large amount of introduction and support. It takes time and practice to get students to become independent corpus users, knowing how to formulate relevant corpus queries and interpret the results. Working with corpora is a method that some students appreciate while others, especially weak students, find it difficult or boring. Several of the students did not find corpora very useful for learning about grammatical rules, but realized the potential of using corpora when writing texts in English.