Objective: To examine the nature and scope of pain in persons with cerebral palsy (CP). Design: Standardized interviews to assess demographics, pain experiences, and the impact of pain on activities. Subjects: Ninety-three adults with CP recruited from medical clinics at the University of Washington and local residential and community housing for persons with developmental disabilities. Main Outcome Measures: Weekly and 3-month pain intensities, chronic pain grade, interference in daily activities caused by pain, and pain-exacerbating and pain-relieving factors. Results: Sixty-two subjects (67%) reported one or more areas of pain of greater than or equal to 3 months' duration. Lower extremity pain and back pain were the most common complaints. Fifty-six percent of the subjects reporting pain indicated it occurred daily. Mean average pain intensity, graded on a scale of 0 (no pain) to 10 (pain as bad as could be), was 3.16 (SD = 2.45) in the preceding week and 4.45 (SD = 2.34) in the previous 3 months. Approximately 53% of subjects reporting pain indicated their average pain was of moderate to severe intensity (average pain rated as greater than or equal to 5). Using Von Korff's Chronic Pain Grade classification system, the majority of subjects who reported pain fell into either grade I (low disability, low pain intensity; 51%) or grade II (low disability, high pain intensity; 39%). Subjects reported many factors that exacerbate pain (eg, stress or weather) or decrease it (eg, exercise or rest). Conclusions: The data suggest that pain is common in adults with CP In many subjects, pain levels were moderate to intense. (C) 1999 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation.