Although instructional development has become an important topic in higher education, little is known about the impact on teaching practice. In this study we investigate the impact of instructional development on teachers' teaching behaviour as perceived by students. Quantitative student data were assembled for 15 experimental and 12 control teachers. 45 experimental students and 27 control students were interviewed. Repeated measures analyses of variance and analyses of covariance showed no statistically significant impact of instructional development on teaching behaviour. The analysis of the qualitative data sustained this result. Several interpretations and perspectives for further research as well as for the planning of instructional development are discussed.