Youth problem gambling is viewed as an emergent public health issue in many countries, and is also an emerging area of public concern in Portugal. However, there is currently no Portuguese instrument that focuses specifically on the measurement of problem gambling among young people. Consequently, the present study aimed to validate the DSM-IV-MR-J for use among Portuguese adolescents and to examine its' psychometric properties. A cross-cultural adaption of this instrument to the Portuguese language was performed using the translation and back translation method. The final version of the instrument was administered to 753 Portuguese high school and first year college students. The findings revealed an acceptable internal reliability and replicated the one-factor structure of this scale. Based on these findings, the Portuguese DSM-IV-MR-J appears to be a valid and reliable instrument, and provides a much needed psychometric tool for the development of more research on youth gambling in Portugal.