In this article we present a secondary analysis of data from a brief cognitive-behavioral intervention for women with rheumatoid arthritis that resulted in significant overall improvements in personal coping resources, pain coping behaviors, psychological well-being, and fatigue. Not every participant, however, improved during the intervention. Establishing predictors of improvement in brief interventions is important to optimize the cost-effective use of these resources. In search of predictors of improvement, we examined demographic and background variables, personal coping resources, pain coping behaviors, and social support. Both linear and quadratic effects were analyzed, comparing baseline measures to both immediate postintervention and 3-month follow-up outcomes using standardized indexes ofpredictors and criteria variables. After removing the effects of baseline scores on the outcomes index, significant predictors of improvement included length of time since diagnosis, personal coping resources, and maladaptive and adaptive pain coping behaviors. Both linear and quadratic effects were found, although this varied as a function of type of predictor.