In the sixties and seventies operant technology was used for the development of stammering treatment programs. Initial successes could not be maintained, which led to a marked decline. Some of the reasons for this are: lower effectivity than originally stated; limited clinical relevance; rigid structure which is uninspiring for the therapist; little room for individualizing the programs despite heterogeneity of clients. More recent treatments reduce these shortcomings with higher flexibility and use of cognitive techniques.