Two quantitative measures for Waters'1 tension-type head ache and migraine severity continuum are proposed. To ensure face validity, symptoms and precipitants of this disorder were compiled from the literature as a basis for the Auckland Migraine and Headache Inventory. This inventory was completed by 84 participants (mean age ± SD, 26.0 ± 9.7 years; range, 18 to 59 years) who complied with the criteria of the International Headache Society, for migraine of tension-type headache. The migraine headache index and the number of precipitants were derived from the Auckland Migraine and Headache Inventory. These scores yielded significant internal reliability ( r s =.77 and .84), test-retest reliability ( r s =.86 and .74), and concurrent validity ( r s =.57) coefficients. The data, therefore, support the notion that the migraine headache index and the number of precipitants are reliable and valid indices of tension-type headache and migraine severity, suitable for participant selection and assessment of treatment. This study offers support for Waters'1 suggestion that tension-type headache and migraine are extremes of a severity continuum.