A single blind, age and gender matched, comparative measurement study was designed to assess active range of cervical motion and passive range of rotation in cervical flexion in asymptomatic and cervicogenic headache subjects. Both procedures are commonly used in clinical practice to evaluate patients with cervicogenic headache. We studied 20 women and eight men with side dominant cervicogenic headache (mean age 43.3 years) matched with 28 asymptomatic subjects. Two experienced manipulative therapists, who were blind to each other's measurement, noted active ranges of cervical motion and passive cervical rotation performed in the flexion-rotation test using the Cervical Range of Motion Device. Headache severity was assessed by a questionnaire. Additionally, one therapist prior to neck motion assessment determined the dominant symptomatic cervical motion segment. Active cervical motion in each direction was identical between the cervicogenic and control groups. In contrast, average rotation in flexion was 44 degrees to each side in the asymptomatic group and 28 degrees towards the headache side in the symptomatic group. C1-2 was deemed to be the dominant segmental level of headache origin in 24 of 28 subjects. In those 24 subjects range of rotation during the flexion-rotation test was inversely correlated to headache severity.