OBJECTIVE Overall and ethnic specific prevalences of bad headache including migraine, for the New Zealand population, are unknown. A study was carried out in South Auckland to estimate prevalence and to explore ethnic differences in doctor attendance for the diagnosis and management of bad headaches. METHODS Telephone interviews were administered to respondents selected by random digit dialing of households. RESULTS 40.6% of the respondents suffered from bad headaches. 54.5% of these had the characteristics of bad headache with features symptomatic of migraine. Trends in the prevalence of bad headache with features symptomatic of common migraine, peaked between the ages of 30-49 years in both men and women. A difference was seen in the prevalence of bad headache with aura, with or without common migraine features, when ethnic groups and gender were examined. The difference in prevalence of aura was particularly noticeable between Pacific Island men and women. Although there was no difference between ethnic groups in doctor attendance, headaches were more likely to be labelled as migraine in Europeans than in the Polynesian groups. CONCLUSIONS Ways in which people perceive and report their bad headaches have a bearing on management by general practitioners. Although no overall ethnic predominance was seen, there was a gender difference amongst Pacific Island people in reporting bad headaches with aura. The labelling process, and thus the management by general practitioners does demonstrate likely ethnic differences.