We compared data from 243 patients with episodic migraine (EM) and 132 patients with chronic daily headache (CDH). We divided the latter group into those with tension-type headache only (CDH Type 1) and those with headaches having migrainous features (CDH Types 2 + 3) and compared each with the EM group and all three groups with one another. CDH Type 1 patients differed from those in the other groups by virtue of gender (more often male) and mean age at headache onset (older). The CDH Types 2 + 3 and EM groups differed only in that the former were more likely to have undergone a brain-imaging study. These data suggest that CDH Type 1 may represent a distinct headache syndrome, while CDH Types 2 + 3 closely resemble episodic migraine.