Objectives: to construct and validate an instrument for assessing the functionality of individuals with schistosomiasis., Methods: methodological study, developed in three stages: 1) construction of the instrument and its association with categories of the International Classification of Functionality, which the study used to elaborate the questions; 2) validation of content, performed by judges experts in the subject; 3) application of the instrument by the test-retest technique in the population with schistosomiasis in 14 days. The study used the correlation coefficient kappa to calculate the degree of agreement between the judges kappa., Results: in its final version, the instrument consists of 27 items, 9 of which are from the Body functions component, 6 from Body structures, 4 from Activity and participation, and 8 from Environmental factors., Conclusions: the constructed instrument has a biopsychosocial approach, considering four components of the ICF, besides presenting good validity and interobserver reliability.