This study developed a short form of the Attitudes and Beliefs Scale-2 (ABS-2), a measure of Ellis’s irrational and rational beliefs. We compared the short form (ABS2-SF) to the longer original scale with 2096 participants, including clinical outpatients, American and Romanian college students, and drug/alcohol rehab residents. The ABS-SF correlated highly with the Original ABS-2. Confirmatory Factor Analyses yielded an excellent fit for an eight-factor bifactor model with factors for the irrational and rational cognitive processes and a general factor. The resulting subscales had excellent internal reliability. The ABS2-SF were highly correlated with measures of mental health problems, and these correlations were significantly higher with the symptom distress subscale than with the troubled social relationships subscale. Correlations with screening measures for DSM-4 disorders showed that the correlations significant but higher for disorders that represented disturbed negative emotions such as anxiety and depression and less with disorders characterized by dysfunctional behaviors. The ABS2_SF scores were significantly higher in a clinical sample than in a college sample. The results have implications for future REBT research that assess irrational and rational beliefs and clinical implications for potentially targeting treatment.