This study assessed the environmental conditions surrounding headache for a clinical sample of 38pediatric headache patients. A parent rating questionnaire, the Children's Headache Assessment Scale(CHAS), was developed and pilot tested as a means of identifying particular environmental events or situations impacting on children's headaches. CHAS items are organized into six functional categories (Stress Antecedents, Physical Antecedents, Attention Consequences, Escape Consequences, Coping Responses, and Medication Use) potentially related to headache activity. Patents filled out the CHAS at an intake evaluation for behavioral medicine treatment, and parents of children who completed treatment filled out another CHAS after therapy. Results showed that the frequency of specific CHAS items varied widely both within and between functional categories, suggesting that headache is affected by a variety of situational factors, some of which are common across many children and others of which are pertinent only for a small proportion of children. The results further suggest that the environmental conditions of headache are open to change by behavioral medicine treatment. In the present study, items reflecting social attention to headache, interference of headache with school attendance, and use of relaxation procedures changed after treatment. The potential value of the CHAS for treatment planning is discussed.