Objective: Excessive, pervasive, and uncontrollable worry are included in the diagnostic criteria of generalized anxiety disorder. Pathological worry is thought to be the cognitive component of anxiety and to be used as a moladaptive defense mechanism However, negative outcomes of pervasive and uncontrollable worry are not restricted to anxiety disorders alone, A growing number of studies point out that pathological worry is associated with panic disorder, obsessive compulsive disorder, depression, sleep disorders and psychotic disorders, Also pervasive and uncontrollable worry is significantly correlated with medical problems such as heart diseases, diabetes and cancer. In order to assess levels of worry several instruments were developed; for example The Worry Domains Questionnaire (Tallis et at 19921, The Anxious Thoughts Inventory (Wells 1994), The Meta Worry Questionnaire (Wells 1995), The Meta Cognitions Questionnaire -30 (Wells, Cartwright-Hatton, 2004). However, Penn State Worry Questionnaire (PSWQ) is the most commonly utilized measure on assessing pathological worry, This self-report measure has been translated into many languages. The measure has shown excellent psychometric properties in studies among non-clinical and clinical populations. The aim of this study was to translate the instrument into Turkish and to assess the factor structure of the instrument in a Turkish sample.