The purpose of this study was to identify, describe and interpret group processes occurring in tutorials in problem-based learning. Another aim was to investigate if a combination of Steiner's (Steiner, I. D. (1972). "Group process and productivity". New York: Academic Press.) theory of group work and Bion's (Bion, W. R. (1961). "Experiences in groups". New York: Tavistock Publications Limited.) theory of work and regression in groups may be a fruitful way to interpret and explain group dynamics in problem-based learning. Data have been collected through a multi-strategy approach. The principal method for data gathering was qualitative. The quantitative method was used as a follow-up study. The data gathering methods used were observation, questionnaire and interviews. The results disclose that it is possible to give a comprehensive and descriptive picture of the group processes that occur in tutorials. The results also show that a combination of Steiner's and Bion's theories may be a fruitful way to describe, interpret and explain group dynamics in tutorial groups. By combining the theories a scheme for understanding group processes was created. The combination, in form of a new model, can be considered as a way of developing the theories and at the same time, it offers a theoretical tool for research purposes. The combination represents a new way of categorising group processes and can hopefully provide a better understanding of interactional dynamics in groups and account for greater explanation value with respect to group processes.