Members of the Japan Pharmaceutical and Diabetes Society, including Certified Diabetes Medication Therapy Pharmacists and Diabetes Medication Therapy Trainees, collaborate with various professionals to support patients undergoing diabetes management. To visualize the effective operation of the certification system and its impact on clinical and educational practices for diabetes medication, a survey was conducted among society members to compare the involvement in diabetes care between those who have obtained certification and those who have not. Responses were received from 367 individuals. The comparison between pre-certification and post-certification showed that more than 50% of both certified and trainee pharmacists felt more confident in their interactions with patients, physicians, and other pharmacists. Certified pharmacists had a significantly higher response rate than trainees in three areas: involvements with physicians, community healthcare professionals, and student education (p<0.05). The category of instruction in self-injection and other techniques were found to have a low level of involvement, and a significant difference was observed between those who have obtained certification and those who have not. In the category of involvement for patients, no significant difference was observed among the certified pharmacists, but a significant difference was observed in involvement with medical professionals other than doctors and nurses, as well as students, and in regional collaboration and research activities. It was possible to clarify that this certification system is useful in improving diabetes care.