The objectives of the study were to analyze the psychometric properties, factor structure and internal consistency of the Spanish version of the Thought-Shape Fusion Questionnaire (TSF-Q), as well as to determine its validity by evaluating the relationship of the TSF-Q to different instruments. Two groups were studied: one comprising 146 patients with a diagnosis of anorexia (n = 82), bulimia (n = 33) or unspecified eating disorder (n = 31), and another group of 115 undergraduates with no history of psychological disorder.All participants completed the TSF-Q, TAF-Q, EDI-2, STAI, BDI and SCL-90-R. Differences in TSF-Q scores between the diagnostic subgroups were also analyzed. Two factors were obtained which coincided with the two sections indicated by the authors of the questionnaire: conceptual and interpretative. The internal consistency of the TSF-Q and its subscales was determined by means of Cronbach’s alpha, with values ranging between .93 and .96. The correlations with other instruments reflected adequate validity. There were no significant differences between the diagnostic subgroups. The Spanish version of the TSF-Q meets the psychometric requirements for measuring thought-shape fusion and shows adequate internal consistency and validity. Keywords:thought-shape fusion, eating disorders, cognitive distortion, psychometric validation. Los objetivos del estudio fueron analizar las características psicométricas del Thougt-Shape Fusion Questionnaire (TSF-Q), su estructura factorial y consistencia interna, así como las relaciones del TSF- Q con diferentes instrumentos para determinar su validez. Se estudiaron 146 pacientes con anorexia (n = 82), bulimia (n = 33) o trastorno de la conducta alimentaria no especificado (n = 31), y un grupo de 115 estudiantes sin antecedentes de interés psicopatológico. Todos completaron el TSF-Q, TAF-Q, EDI-2, STAI, BDI y SCL-90-R. Las diferencias en las puntuaciones del TSF-Q entre los subgrupos diagnósticos fueron también analizadas. Se obtuvieron dos factores, coincidentes con las dos secciones conceptual e interpretativa señaladas por los autores del cuestionario. La consistencia interna del TSF-Q y de sus subescalas se determinó mediante el coeficiente alfa de Cronbach, que osciló entre .93 y .96. Las correlaciones con otros instrumentos reflejaron una adecuada validez. No hubo diferencias significativas entre los subgrupos diagnósticos. El TSF-Q, en su versión española, cubre los requisitos psicométricos para medir la fusión pensamiento- forma y presenta adecuada consistencia interna, así como una adecuada validez. Palabras clave: fusión pensamiento-forma, trastornos de la conducta alimentaria, distorsión cognitiva, validación psicométrica. Psychometric Properties of the Spanish Version of the Thougth-Shape Fusion Questionnaire Ignacio Jáuregui Lobera 1 , Miguel Angel Santed 2 , Roz Shafran 3 , María José Santiago 4 , and Sonia Estébanez 4 1 Universidad Pablo de Olavide (Spain) 2 Universidad Nacional de Educación a Distancia (Spain) 3 University of Reading (UK) 4 Instituto de Ciencias de la Conducta (Spain) The Spanish Journal of Psychology Copyright 2012 by The Spanish Journal of Psychology 2012, Vol. 15, No. 1, 410-423 ISSN 1138-7416 http://dx.doi.org/10.5209/rev_SJOP.2012.v15.n1.37347 Correspondence concerning this article should be addressed to Ignacio Jáuregui Lobera. Virgen del Monte 31. 41011 Sevilla (Spain). Phone: +34 954280789. Fax: +34 954278167. E-mail: igjl@upo.es & ijl@tcasevilla.com 410