The aim of this study is to learn about the psychometric properties of the Spanish adaptation of a scale of perceived self-efficacy in informational competence. The questionnaire was administered to 192 students of the Spanish Master´s Degree in Secondary Education Teacher Training. The instrument, adapted from Pinto (2009), has 26 items grouped into four categories. In this article we analyse the self-efficacy dimension of this instrument, and include a validity and reliability analysis. Internal consistency is measured using Cronbach's α coefficient, and factor analysis is used for construct validity. Results show the internal consistency of the questionnaire (alpha 0.903). In terms of structure, we found two additional factors with regard to what was expected. In conclusion, the modified scale is a valid and reliable instrument, which allows exploring subdomains of particular relevance for the development of informational competence among future secondary education teachers.