Objective The study purposed to perform content validation and verification of the reliability of an instrument in the form of a questionnaire, called “ Oral Health Literacy for Diabetics “. It was designed to investigate whether there was access, understanding, appraise and practice of information related to oral health among diabetics. Methods This is a methodological research that was carried out through the application of the Oral Health Literacy for Diabetics between 109 diabetic patients, since at least 60 participants should be considered in studies using test/retest. The research complied with the ethical principles of research. The content validation was performed by dentists, acknowledging the relevance and the ability to measure the levels of literacy of each item of the Oral Health Literacy for Diabetics. The reliability/reproducibility was estimated by the test/retest in an interval of seven to fifteen days by Kappa, using the SPSS®. Results The results showed that the content of the Oral Health Literacy for Diabetics presented relevance and ability to measure the levels of literacy in oral health among diabetics. The results of the Kappa ranged from -0.09 to 1. Only 16 of the 150 questions did not have satisfactory levels of agreement, i.e., Kappa smaller or equal to 0.60. We chose to synthesize the Oral Health Literacy for Diabetics initially with 150 questions, for a version with 30 questions. Conclusion It is concluded that the Oral Health Literacy for Diabetics was considered valid with respect to the content and that a general form its reliability was satisfactory. It is recommended to use the Oral Health Literacy for Diabetics in academia and in health services aiming to improve the quality of life of diabetic patients.