Background: Continuing Medical Education (CME) is a cornerstone of improving competencies and ensuring high-quality patient care by nurses and physicians. The Ministry of Health (MOH) Malaysia collaborated with Steno Diabetes Centre to improve diabetes-related competencies of general physicians and nurses working in primary care through a six-month training programme called the Steno REACH Certificate Course in Clinical Diabetes Care (SRCC).Objective: This impact evaluation aimed to assess the effect of participation of general physicians and nurses in the SRCC in selected public primary healthcare clinics in Kuala Lumpur and Selangor, Malaysia.Design: The quasi-experimental, embedded, mixed-methods study used concurrent data collection and the Solomon four-group design. Participants in an intervention group (Arm 1) and control group (Arm 3) were assessed by pre-and post-test, and participants in separate intervention (Arm 2) and control (Arm 4) groups were assessed by post-test only. Quantitative and qualitative methods were used to assess the effect of the programme.Results: Thirty-four of the 39 participants in the intervention groups (Arms 1 and 2) completed the SRCC and were included in the analysis. All 35 participants in the control groups (Arms 3 and 4) remained at the end of the study period. Significant improvements in diabetes-related knowledge, skills and clinical practise were found among general physicians and nurses in the intervention group after the six-month SRCC, after controlling the pretest effects. No clear changes could be traced regarding attitudes.Conclusion: SRCC participants had significant improvements in knowledge, skills and clinical practice that meet the current needs of general physicians and nurses working in primary care in Malaysia. Thus, SRCC is an effective CME approach to improving clinical diabetes care that can be scaled up to the rest of the country and, with some modification, beyond Malaysia.