Introduction. Infantile headache is an increasingly important cause of medical consultation, due both to its increasing prevalence and its subsequent repercussion on the child’s life. Also, certain sleep disorders (parasomnias) are commoner in infancy than in later life. The relationship between headache and sleep disorders is not clear, but from the literature it would seem that there is an association, at least in some types of headache, in adults. Patients and methods. In order to determine possible alterations in patterns of sleep in children with chronic headache (a history of headache during the previous six months occurring more than 15/month or 180 days/year) we carried out a comparative study on a total of 224 Valencian children aged between 3 and 15 years. Of these, 97 children had been diagnosed as having primary chronic headache (cases) in a specialized Paediatric Neurology clinic. Twenty seven healthy children with no history of headache (controls) were found amongst the pupils of a Valencian state school. Using a purpose-designed sleep questionnaire, data was obtained as to the duration, hygiene, quality and incidence of parasomnia in the two groups. Results. The results showed a decrease in duration of sleep at night, increased frequency of poor sleep hygiene, increased prevalence of certain sleep disorders (insomnia and nocturnal wakening), of certain parasomnias (somnambulism, somniloquy, enuresis) and of nocturnal snoring, all of statistical significance (test c2 with p< 0.005). Conclusion. In children there is an association between chronic headache and certain sleep disorders [REV NEUROL 1999; 28 (Supl 2): S 150-5].