Since prescribed wear times of removable appliances are, in combination with comfort, relevant to compliance, a questionnaire on the prevalence, the nature and the differentiation of such prescriptions in active orthodontic treatment was sent to 300 orthodontists selected at random among the members of the German Orthodontic Society. On the basis of 172 responses (response rate 57.5%), the following results were obtained: In eight to 16-years olds "active" treatment is administered with Schwartz plates in an average of 43.7%, and with functional orthopaedic appliances in an average of 37.6% of the cases, the classical activator (61.1%) and the bionator (58.7%) being used most frequently. Particular times of day or night are prescribed as wear times by some 60% of responders, while others prescribe merely a certain number of hours of daily wear. Identical prescriptions are given to the majority of patients by 86.6%, and are unchanged throughout the course of active treatment by 73.8%. Wear times actually prescribed average 15 (functional appliances) and 16 hours (plates) daily, while the minimum wear time considered necessary for successful treatment averages 12.8 for functional appliances and 13.9 for plates.