The Attitudes and Belief Scale-2 (ABS-2) developed in the late 1980s, is a measure of Ellis’ irrational and rational beliefs. Although no publication has described the instrument and it has only appeared in conference presentations, many researchers have used the ABS-2 to test REBT. This article describes the development of the ABS-2 and the original research on its psychometric properties. The scale has three factors that represent 24 different cells in a 4 × 2 × 3 factorial model. The first factor, Cognitive Processes, reflects Ellis’ concepts of Demandingness, Awfulizing, Frustration Intolerance, and Self-Downing. The second factor covers irrationally worded items versus rationally worded items. The rationally worded items were written to counter the irrational beliefs. The third factor includes content or life themes about which the person could be concerned, and includes Achievement, Affiliation, and Comfort. The ABS-2 generates a Total Score, a Total Irrationality Score, a Total Rationality score, and Scales scores representing each of the four Cognitive Processes domains and each of the three Content domains. The ABS-2 scores demonstrate adequate to excellent internal consistency, and correlate significantly with measures of depression, anxiety, life satisfaction, selfcontrol, well-being, and measures of internalizing personality disorders. The ABS-2 did not correlate significantly with measures of anger, externalizing personality disorders, mania, and somatoform disorder. An exploratory factor analysis provided weak support for the factor structure of the scale. The ABS-2 scores distinguish between normal and clinical samples. Rationally worded items discriminated between clinical and nonclinical groups much better than did the irrationally worded scales, suggesting that instruments that only assess irrational beliefs might underestimate the support for REBT.