Objectives To evaluate the methodological quality of the Palestinian Clinical Practice Guideline for Diabetes Mellitus using the Translated Arabic Version of the AGREE II. Design Methodological evaluation. A cross-cultural adaptation framework was followed to translate and develop a standardised Translated Arabic Version of the AGREE II. Setting Palestinian Primary Healthcare Centres. Participants Sixteen appraisers independently evaluated the Clinical Practice Guideline for Diabetes Mellitus using the Translated Arabic Version of the AGREE II. Main outcome measures Methodological quality of diabetic guideline. Results The Translated Arabic Version of the AGREE II showed an acceptable reliability and validity. Internal consistency ranged between 0.67 and 0.88 (Cronbach’s α). Intra-class coefficient among appraisers ranged between 0.56 and 0.88. The quality of this guideline is low. Both domains ‘Scope and Purpose’ and ‘Clarity of Presentation’ had the highest quality scores (66.7% and 61.5%, respectively), whereas the scores for ‘Applicability’, ‘Stakeholder Involvement’, ‘Rigour of Development’ and ‘Editorial Independence’ were the lowest (27%, 35%, 36.5%, and 40%, respectively). Conclusions The findings suggest that the quality of this Clinical Practice Guideline is disappointingly low. To improve the quality of current and future guidelines, the AGREE II instrument is extremely recommended to be incorporated as a gold standard for developing, evaluating or updating the Palestinian Clinical Practice Guidelines. Future guidelines can be improved by setting specific strategies to overcome implementation barriers with respect to economic considerations, engaging of all relevant end-users and patients, ensuring a rigorous methodology for searching, selecting and synthesising the evidences and recommendations, and addressing potential conflict of interests within the development group.