The purpose of the present study is to investigate reliability and validity of the Italian version of Survey of Perceived Organizational Support (eight items). In a first study employees from three independent samples completed the questionnaire (total N = 550): private firms, public schools and private vocational training bodies. Confirmatory factor analyses using the multiple-group method revealed that a one-factor model, that assumes that all items load on one single factor, fitted the data of groups. Moreover an invariance of three item loadings, among groups, was founds. Internal consistency was good. In a second study 117 employees completed the questionnaire with the full Survey of Perceived Organizational Support and the organizational commitment scale. These results shows a acceptable convergent validity. New studies are needed to clarify the discriminant validity of the SPOS-I.