Objective: To investigate headache specifically associated with the cervical spine, and factors associated with it. Design: Cross-sectional, population-based observational study. Setting: Two agriculturally based municipalities in southern Tasmania, Australia. Patients: Four hundred fifty adults were randomly selected from electoral rolls; after refusals and exclusions, 427 subjects participated. Outcome Measure: For analysis, subjects were divided into three groups: those who did not have a particular type of headache in the previous month, those reporting fewer than two headaches of this type for the month (occasional headache), and those reporting two or more (frequent) headaches of this type in the month. Study Factors: Information collected by questionnaire and by objective measurement on anthropometric and functional measurements, wearing glasses or dentures, usual occupation, and usual recreational activities. Results: The monthly prevalence of frequent headaches associated with the cervical spine was 28.3% (95% confidence interval [CI], 24.2-32.9), and another 35.4% (30.9-40.1) of subjects had these headaches occasionally. The frequency of headache occurrence was associated with a difference between front and back neck length of 2 cm or more. Occasional participation in recreational sport by men and wearing glasses by women were significant predictors of headache. Conclusion: Headaches of this type were more frequent in subjects with a long anterior neck length relative to their posterior neck length, particularly if they occasionally participated in recreational sports (men) or wore glasses (women).