BACKGROUND: The categorical approach to diagnosing mental disorders has been criticized for a number of reasons (e.g., high rates of comorbidity; larger number of diagnostic categories and combination). Diverse alternatives have been proposed using a hybrid or totally dimensional perspective. Despite the evidence supporting use of the Multidimensional Emotional Disorders Inventory (MEDI) for assessing the transdiagnostic dimensions of Emotional Disorders using a dimensional-categorical hybrid approach, no data exist on Spanish clinical samples. The present study explores the validity and reliability of the 49-item MEDI in a clinical sample and provides data for its use. METHODS: A total of 280 outpatients with emotional disorders attended in different Spanish public Mental Health Units in Spain filled out all questionnaires during the assessment phase and the MEDI again one week after. The instruments used evaluate four main constructs: personality, mood, anxiety and avoidance. RESULTS: The nine original factors were confirmed and showed adequate reliability (α: 0.66-0.91) and stability (r = 0.76-0.87). No differences in mean scores by sex were presented in any subscale (p ≥ .07). The MEDI subscales correlated significantly with the scales of each of the selected constructs (0.45 < r < 0.76). LIMITATIONS: The main limitations of this study were the limited sample size and not being able to count on MEDI scores post-transdiagnostic intervention. CONCLUSIONS: The MEDI demonstrates adequate reliability and validity. It allows to assess diverse symptoms efficiently, thus being of interest for clinical studies and practice.