The objective of this study was to develop and evaluate a scale for assessing irrational thoughts among burned patients. The present study was mixed (qualitative-methodologic) which was performed in several stages such as investigating similar or related scales, interviewing with patients and psychologists. Content validity was calculated by modified KAPPA basis on relevance and clarity. The reliability of the scale was measured using internal consistency and the test–retest method. To determine the construct validity, exploratory factor analysis approach using maximum likelihood extraction with varimax rotation was conducted. A total of 329 burned patients were recruited from Tehran, Tabriz, and Kermanshah provinces of Iran. Modified kappa scores were 0.80 and 0.91 for relevance and clarity of the items included in scale. The Cronbach alpha for overall scale, subscale 1, and subscale 2 were 0.89, 0.88, and 0.8, respectively. Test–retest reliability was also acceptable (intraclass correlation coefficient = 0.80). The best solution from the maximum likelihood analysis of the 39 items of the scale revealed two factors corresponding to the two subscales with 14 items that subscale 1 (self-acceptance) consisted of 10 statements accounting for 60% of the variance (eigenvalue = 5.04) and subscale 2 (distastefulness and pity) consisted of four statements accounting for 40% of the variance (eigenvalue = 1.53). The scale reflects acceptable levels of validity and reliability in assessing the irrational thoughts among Iranian patients. Moreover, the testing populations of both patients with burned faces and patients with other burned body parts indicates that the scale may also be applicable for patients’ burn disfigurements on any part of their bodies.