Compared the efficacy of a school-based, nurse-administered relaxation training intervention to a no-treatment control condition for children (10-15 years old) with chronic tension-type headache and the outcome at posttreatment and a 6-month follow-up. The study was conducted in a controlled between-group design including 26 schoolchildren who were randomly assigned to the two treatment conditions. Results showed that headache activity in the children treated with relaxation training was significantly more reduced than among those in the no-treatment control group at posttreatment as well as the 6-month follow-up. At these evaluations, 69% and 73% of the pupils, respectively, treated with relaxation had achieved a clinically significant headache improvement (at least a 50% improvement) as compared to 8% and 27% of the pupils, respectively, in the no-treatment control group. Thus, a school-based, nurse-administered relaxation training program seems to be a viable treatment approach for children with chronic tension-type headaches.