Objective. To predict the 2-year course of activity limitations in patients with early knee and/or hip osteoarthritis (OA). Methods. The Cohort Hip & Cohort Knee (CHECK) study is a prospective followup study. The CHECK cohort, comprising participants (n = 1,002) with early OA-related knee and/or hip symptoms, was followed for 2 years. Participants completed questionnaires and underwent physical, laboratory, and radiographic examination. Regression models were used to examine whether baseline variables predicted the course of activity limitations as measured with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Analyses were performed separately for participants with knee symptoms and participants with hip symptoms. Results. After 2 years of followup, activity limitations slightly decreased. Large between-subject variation was observed in WOMAC change scores. In participants with knee symptoms, young age, non-Western ethnicity, bilateral hip pain, morning stiffness in the knee, high comorbidity count, high body mass index, high bodily pain, poor general health perception, and pain coping strategy were associated with a poor 2-year outcome on activity limitations. In participants with hip symptoms, few activity limitations at baseline, bilateral hip pain, morning stiffness in the knee, high comorbidity count, low active hip flexion, poor general health perception, and pain coping strategy were associated with a poor 2-year outcome on activity limitations. Conclusion. After 2 years of followup, large between-subject variation was observed in the course of activity limitations. The course of activity limitations is to some extent already predictable at an early stage of knee and hip OA. © 2010, American College of Rheumatology.