This research is in response to an interest in groupwork practices. Concerns among colleagues in Greece, about the lack of collaboration within Greek primary classrooms prompted this investigation. The purpose of this research was to explore possible changes in students' attitudes and behaviour when moving from traditional class teaching to group work.This research is based on the theoretical background of social constructivism The investigation was carried out in the context of word problem solving in two grade-four classes of a Greek primary school in England. Data was gathered and analysed mainly using interpretative methods, but some quantitative methods were incorporated. The methodological approach consisted of case study combined with elements of teaching experiment and action research.After a pilot study, two linked case studies were carried out. Pre-tests and posttests were administered, pre-interviews and post-interviews were conducted, pre-questionnaires and post-questionnaires were completed, and whole class and group conversations were tape-recorded.The analysis of the data collected suggests that both case studies were successful in establishing a collaborative environment. In both cases, the students changed their attitudes towards group work and problem solving, and some changes regarding their learning behaviour were also observed. The style of teaching appeared to be important in facilitating classroom debate, both in group and whole class discussion.The unique contribution of this study is that it looks closely at the processes involved during a change from a very traditional class (teaching) to a group working scheme carried out in real classrooms with real students, and reports the problems that arose. ACKNOWLEDGEMENTS