This study investigates the associations between obesity and migraine. A neurologist clinically assessed 684 women aged 40–74 years attending a population-based mammography screening programme. Body height and weight were measured and body mass index (BMI) calculated. Obesity was defined as a BMI ≥ 30 kg/m2. The proportion of obesity did not differ between women with active migraine, women with inactive migraine or women who had never experienced migraine (P = 0.96). The distribution of frequency, intensity, duration or severity of attacks did not differ between obese and non-obese women with migraine. In this study there were no significant associations between migraine or migraine characteristics on the one hand and obesity on the other.