Multiple sclerosis is a chronic neurological disease which can cause a variety of symptoms (motor and sensory impairment, visual problems, bladder and bowel problems, sexual dysfunction, and decline in cognitive function). Both the Medical Outcome Study Short Form-36, a generic questionnaire regarding health-related quality of life, and the Disability and Impact Profile, a similar questionnaire developed for people with chronic diseases, are used regularly to assess patients with multiple sclerosis. Over a 6-mo. interval 187 patients with multiple sclerosis completed these questionnaires twice. Internal consistency of both questionnaires at Times 1 and 2 was .60 or above for all eight scales of the Medical Outcome Study Short Form-36 and five scales of the Disability and Impact Profile. Estimates of test-retest reliability for three scales of the Medical Outcome Study Short Form-36 were below .60, but for all scales of the Disability and Impact Profile were .60 or higher. The two questionnaires appeared to be reliable for our sample of patients with multiple sclerosis.