Inter-observer agreement among 4 pediatric neurologists in the diagnosis of recurrent headaches in 40 children, ages 4 to 17 years (mean 10 years), was prospectively assessed at the University of Manitoba, Winnipeg, Canada. Referring to letters containing reports of the child’s symptoms, history and examination, the headache diagnoses were checked off on a data sheet, listing up to 12 types. Agreement in headache diagnoses between pairs of neurologists ranged from 45% to 78%. Agreement was 76% when both neurologists in a pair diagnosed single headache types, but only 4% when multiple diagnoses were applied. 
COMMENT. Agreement among pediatric neurologists was relatively good provided that a single headache type was diagnosed. The International Headache Society recommendations for classification of all headache types in a single patient may lower inter-observer agreement on diagnoses in children. For purpose of evaluation of pharmacological, dietary, or psychosocial treatment regimens, selection of patients with a single headache diagnosis is important. The validity of the classification criteria for childhood headache may need to be re-examined.