Objectives: The use of complementary and alternative medicine (CAM) for diabetes mellitus is becoming increasingly popular; however, little is known about the prevalence of CAM use in patients with diabetes mellitus in Oman. The objectives of this study were to estimate the prevalence of use of CAM among diabetic patients in Muscat region, Oman, and to determine the types of CAM used as well as to identify the demographic features influencing the use of CAM. Methods: The study was performed from May to August 2009 on diabetic patients from 4 health centres in Muscat region. A total of 146 patients were interviewed. Information was obtained on demographics, and the prevalence and pattern of use of CAM. Results: Sixty two (42%) of the participants used CAM for the treatment of diabetes. Thirty (48%) were satisfied about its use and 27 (43%) intend to use it again. The only types of CAM used by participants in this study were herbs (n = 49, 79%), and/or food supplements (n = 7, 11%). Family and friends (n = 47/62, 76%) and/or traditional healers (n = 19, 31%) were the main source of information on CAM in the treatment of diabetes. There was no significant correlation between demographic characteristics and the use of CAM for diabetes. Conclusion: CAM is used widely for diabetes in Muscat region, Oman. Patients have strong faith in CAM in terms of effectiveness. Doctors should recognise this and be prepared to talk more freely with patients about its use and potential side effects.