Several studies of experimental and acute clinical pain have indicated reactive effects of self-assessment on pain intensity and tolerance. A recent study of chronic pain patients (vonBaeyer 1994), however, failed to show these effects. The present investigation sought to determine whether reactive effects can be produced in chronic pain patients by an intensive self-assessment protocol. Using the methodology of ecological momentary assessment (EMA; Stone and Shiffman 1994), thirty-five chronic rheumatoid arthritis patients completed diaries of pain and mood seven times a day for 1 wk. Eighteen patients were included in the final sample because they responded to at least half of the number of hourly prompts for each of the 7 days. Using repeated measures analysis of the daily means, no significant effects of time were found for any measures. Reactive effects that result in an average change in pain levels over time, therefore, do not appear to be produced by intensive self-assessment in a naturalistic context. Results are discussed in terms of cognitive and behavioral theories of pain reactivity.