Abstract. A comprehensive assessment of functioning in schizophrenia is essential to plan appropriate interventions for helping individuals with this health condition. The International Classification of Functioning, Disability and Health (ICF) offers a theoretical framework for assessing functioning and disability. Our aim was to identify the most frequently used measurement instruments reported in studies on functioning in schizophrenia, to conduct a content comparison with respect to the ICF, and to compare the categories extracted from these instruments with those covered by the Brief ICF-Core Set for schizophrenia. A structured literature search of studies on functioning in schizophrenia was conducted using Medline, CINAHL, and PsycINFO. The items of the top 20 measurement instruments were then linked to the ICF classification system. The most commonly used instruments were neuropsychological tests (i.e., Wisconsin Card Sorting Test and Trail Making Test) and measures of clinical symptoms (i.e., PANSS) and general functioning (i.e., GAF). The linking process resulted in 45 ICF categories (25 from Body functions, 1 from Body structures, 14 from Activities and Participation, and 5 from the Environmental factors component). Most of the top 20 instruments are not specifically designed for patients with schizophrenia or for assessing functioning, but rather are general standardized tests widely used to measure a broad range of outcome variables in several health conditions. Our results suggest a lack of an internationally accepted, commonly used, specific and comprehensive gold standard to assess functioning in individuals with schizophrenia.