Chronic illnesses are a significant issue across many health professional domains, becoming an increasing burden on limited and costly resources. The current study investigated the relationship between secondary beliefs and emotional responses, beyond the relationship accounted for by illness perceptions, using the framework of Rational Emotive Behavior Therapy. Sixty-five adults with arthritis participated in the questionnaire-based study. Multivariate analysis found that different emotional representations of the illness were significantly predicted by the individual's secondary belief, above and beyond that predicted by the cognitive representation of their illness alone. The study found that individuals who utilized an achievement secondary belief experienced feelings of worry, whereas individuals who used an approval orientation to understand their arthritis experienced emotions such as depression, being upset, anger, anxiety, and fear. No significant pattern emerged for individuals who used a comfort secondary belief to understand their arthritis. These findings are in line with the theory of secondary beliefs, as articulated by Rational Emotive Behavior Therapy.