Objective: To translate and perform the cross-cultural adaptation of the StarT Back Screening Tool (SBST) questionnaire to assessment and screening low back pain for Portuguese application, and test their reliability. Method: To establish conceptual equivalence in item, semantic and operational concern, there were performed two translations into Portuguese in a independently way. A combined version was obtained by consensus among the authors of the translations in order to be achieved a noticeable version in semantic terms and easy to understand. The synthesis version was administered to 40 subjects distributed by gender, young and older adults, with and without low back pain. Through cognitive interviews with the subjects of the sample, clarity, the acceptability, as well as the familiarization of the Portuguese version was evaluated, promoting the changes necessary for a better understanding. The final Portuguese version of the questionnaire was then back-translated into the original language. To evaluate the SBST-Portugal psychometric properties, 31 subjects with low back pain performed two interviews. Results: Participants interviewees reported that in general the items were clear and comprehensible achieving face validity. The reliability of the SBST-Portugal showed a Kappa value of 0,74 (95%IC 0,53-0,95), and the internal consistency (Cronbach’s alpha) was 0,93 for the total score and 0,93 for the psychosocial subscale. Conclusion: The Portuguese version of SBST questionnaire proved to be equivalent to the original English version and reliable for the Portuguese population with low back pain. Being an instrument of easy access and application it could be use in primary care.