We describe the development of the Arthritis Helplessness Index (AHI), a self-report instrument designed to measure patients' perceptions of loss of control with arthritis. The participants in this research were 219 patients with rheumatoid arthritis (RA) who completed a quantity of mailed materials, including the AHI, functional measures and other psychological scales. Significant evidence of reliability and validity of the AHI was found. Greater helplessness correlated with greater age, lesser education, lower self-esteem, lower internal health locus of control, higher anxiety, and depression, and impairment in performing activities of daily living using a health assessment questionnaire. Over one year, changes in helplessness correlated with changes in difficulty in performing activities of daily living. The AHI appears to be a useful measure for further studies in RA and a valuable clinical tool in monitoring the psychological status of patients with RA.