In 1995, cooperative learning tutorials were introduced into large first year physics classes at the University of Sydney. This paper describes the effect of these cooperative learning tutorials, called Workshop Tutorials, on student learning from both a quantitative and qualitative point of view. It was found that students attending more than half the total number of tutorials scored significantly better over the year than those attending less than half. Student reaction was almost wholly positive, with particular mention made of the voluntary nature of the tutorials as well as the use of practical, 'hands on' demonstrations within the tutorials.