Criteria for the diagnosis of migraine have evolved from generalized descriptions to specific rules designed to ensure the selection of homogenous groups of patients for research studies. For clinical practice, the former are insufficiently specific and the latter are too complex. For care of headache patients by primary care physicians, we propose that the diagnosis of migraine without aura (common migraine) is warranted if any two of the following symptoms are present: unilateral site, throbbing quality, nausea, photophobia or phonophobia. These criteria are derived from a study comparing the features of 100 patients with migraine without aura and 100 patients with chronic daily headache. The proposed criteria for the diagnosis of migraine without aura were highly sensitive and adequately specific in discriminating groups. These simple criteria should facilitate the diagnosis of migraine by primary care physicians.