The aim of this study was to evaluate the validity of the headache diagnoses (migraine and tension-type headache) obtained from short interviews by nurses, where the subjects were asked to identify their headache(s) based on recognition of typical headache descriptions. All students in junior high schools and high schools aged 12-19 years in Nord-Trøndelag county, Norway, were invited to participate in the youth part of the Nord-Trøndelag Health Study ('Helseundersøkelsen i Nord-Trøndelag'-HUNT), 1995-1997. In this cross-sectional study a total of 8984 students (88%) completed a comprehensive questionnaire with different health-related items. Of these, 6149 were also interviewed by nurses about their headache complaints by giving them two alternative headache descriptions in accordance with either migraine or tension-type headache (Head-HUNT-Youth). The headache diagnoses obtained from nurse interviews were validated in a stratified random sample enriched with headache subjects from the interviewed population. Out of 159 invited individuals, 112 (70%) participated in extensive semistructured interviews by neurologists. The overall chance-corrected agreement (kappa) was 0.76 (confidence interval (CI) 0.66-0.86), which is considered good. For migraine, the positive and negative predictive values were 89% and 90%, respectively, and the chance-corrected agreement (kappa) was 0.72 (CI 0.58-0.87). For tension-type headache, positive and negative predictive values were 83% and 91%, respectively, and chance-corrected agreement (kappa) was 0.74 (CI 0.62-0.87). There was good agreement between the headache diagnoses obtained from the short interviews by nurses and the extensive interviews by neurologists. Short interviews based on recognition of typical headache descriptions seem to be an alternative and efficient way to identify migraine and tension-type headache sufferers among adolescents. The method can be useful in epidemiological research, e.g. in estimation of headache prevalence.