The utility of measuring both positive and negative affective states for assessing rheumatoid arthritis (RA) patients was examined in 3 independent samples of male and female RA patients (Sample A: 179 women, 48 men; Sample B: 177 women, 24 men; Sample C: 134 women, 38 men). Confirmatory factor analyses of each sample indicated that positive and negative affect constituted separate, negatively correlated factors. The relations among disease variables, coping, and affects were consistent with a model in which coping mediates the relationship between disease variables and positive and negative affect. Patients with higher pain and limitation from RA had higher levels of maladaptive coping, and maladaptive coping was associated with lower positive affect and higher negative affect. Those RAs with higher activity limitation also reported less adaptive coping, which was associated with less positive affect.