The purposes of the present survey research in diabetic patients were 1) to determine characteristics of complementary/alternative medicine (CAM) use, 2) to identify factors related to CAM use such as sociodemographic, adverse effects, and quality of life, and 3) to determine differences between patients who used and did not use CAM. The data was collected through developed questionnaires and SF-36 scale Thai version. Samples were 159 diabetes patients over 18 years of age or older who came for treatment at Suppasitthiprasong Hospital, Ubon Ratchathani Province, Thailand. The results indicated that the prevalence of CAM use was rather high (47.8%). The most common types of CAM used were yoga/exercise (32.8%), unchanged form of herbal medicine (29.9%), and changed form herbal medicine (17.8%). The average expense of CAM use was dollar 8.58 per person per month. Thus, if the percentage of CAM use and the cost were true for other Thai diabetic patients throughout Thailand, CAM use expenditure for the whole country would be about dollar 915,250-1,545,750 per month, which is quite high for a small country like Thailand. Most patients (64.4%) who used CAM did not inform their doctors about their CAM use. Results also indicated that government official patients were more likely to use CAM than those of farmer patients significantly (p-value = 0.03, odds ratio = 12.11). In addition, the present study found that patients who had a higher income were more likely to use CAM than those of lower income patients significantly (p - value = 0.04, odds ratio = 1.01). However, other factors such as age, sex, marital status, level of education, health insurance coverage status, duration of time to treat, occurrence of adverse effects, and quality of life were not different between the patients who used CAM and who did not use CAM. Physicians should pay more attention to the CAM use of patients since they used CAM without informing physicians and some herbal medicines may cause hypoglycemia. However, the study results had some limitations to apply to other Thai populations since the sample were Suppasitthiprasong patients who may be different from other Thai populations in many ways such as their local culture, belief, and CAM use types and cost.