OBJECTIVES: To develop the clinical practice guideline major depressive disorder for general practitioners in primary and secondary health care setting included the diagnosis, differential diagnosis, severity classification and medical treatments. METHODS: A list of 13 key elements of a CPG development process were developed that consisted of: 1) setting the review teams; 2) determining the problems; 3) determining health outcomes; 4) evidence based literature review; 5) meeting to draft the CPG; 6) formulating draft of CPG; 7) apprising the content of CPG by experts; 8) trail phase; 9) evaluating for trail phase; 10) developing the curricular for CPG training; 11) preparing for CPG training; 12) evaluating;  and 13) improving the CPG related with evaluated results. RESULTS: There were 3 main processes in clinical practice guideline major depressive disorder for general practitioners in primary and secondary health care setting (CPG-MDD-GP) which were 1) Assessment of major depressive disorder (clinical assessment using 9Q screening tool and DSM-TR diagnostic criteria, differential diagnosis, diagnosis for major depressive disorder and coding of diagnosis) 2) Management of major depressive disorder and 3) Management of hospitalized patients. General practitioners were satisfied with the CPG-MDD-GP in trial phase. A total of 416 general practitioners in all provinces were trained to use the CPG-MDD-GP then they would be followed and evaluated.  Psychiatrists in psychiatric hospitals/ institutes would be available for consultation from the general practitioners. CONCLUSIONS: The CPG-MDD-GP should be distributed to all general practitioners in primary and secondary health care setting. Next step, it would be useful for developing the CPG for MDD in the tertiary health care setting.