Population-based data on migraine incidence and comorbidity are scarce. We therefore aimed to quantify incidence rates and comorbidity of diagnosed migraine and health resource utilization (HRU) in migraineurs in the UK primary care setting. We conducted a follow-up study with a nested case-control analysis on the General Practice Research Database. The study encompassed 51,688 patients with a first-time diagnosis of migraine between 1994 and 2001, and the same number of matched controls. The migraine incidence rate was 3.69 (95% confidence interval 3.66, 3.73) cases per 1000 person-years. It was around 2.5 times higher in women. Most chronic diseases were slightly more prevalent in migraineurs than in controls. Triptan users had higher health resource utilization than other migraineurs. This study shows that migraine is a common diagnosis in general practice and associated with a high prevalence of comorbidity. The increased HRU in triptan users suggests greater migraine severity.