Methods of evaluating training courses in behaviour modification for staff working in mental handicap are briefly reviewed. Insufficient attention seems to have been paid to changes in staff behaviour following training. A widely used training package—the E.D.Y. Course—was investigated using a non-equivalent control group design. Four special school teachers were given E.D.Y. training and compared with four control teachers pretraining, post-training and at a fourteen month follow-up. Results indicated that experimental teachers changed their behaviour following training in the expected direction and maintained this change at follow-up. Control group teachers showed no behavioural change from occasion to occasion and scored significantly lower than the experimental group on the dependent variable on each occasion. The results are discussed in terms of the effectiveness of the package and the maintenance and generalization of skills.