Deficiencies in instructional design skill have been identified as a possible cause for the problems teachers of Dutch Polytechnics experience in designing competency-based education. This research investigates the effects of an Instructional Systems Design (ISD) training on teachers’ instructional design behavior. Thirty-six teachers from 16 Dutch Teacher Training Colleges received 20 hours of web-based training either in an ISD based condition or in an experience-based design condition (EXP). In the ISD condition teachers were trained to apply the Four-Component Instructional Design Model (4C-ID model) of . Englewood Cliffs, NJ: Educational Technology Publications, in the EXP condition the teachers were trained to optimize their own approach. The results supported the hypotheses, indicating that the ISD-based training resulted in a higher quality of design and was evaluated more positively than the EXP approach. These findings suggest that training in an ISD approach can effectively support teachers’ instructional design strategies.