Objective:The prevalence of complementary and alternative medicine (CAM) usage among patients with type 2 diabetes mellitus (T2DM) in Indonesia is high.However,to date,little is known about why Indonesian T2DM patients choose CAM therapies,how their knowledge,attitude and practice (KAP) of CAM affects their choices,or how demographics correlate with patient choices.Therefore,this study aimed to investigate the KAP and predictors of CAM usage in T2DM patients in Indonesia.Methods:This was an observational,cross-sectional study.Patients were interviewed using a question-naire.Chi-square tests or Fisher\'s exact tests were used to compare demographic and clinical data,as well as KAP assessments,between T2DM patients who use and do not use CAM.Multivariate logistic regres-sion analyses were used to investigate predictors of CAM usage.Results:A total of 628 T2DM patients were enrolled in the study.CAM therapies were used by 341 patients (54.3％).The most common therapies were herbs and spiritual healing,used by 100.0％ and 68.3％ of CAM-using patients,respectively.CAM therapies were frequently recommended by family mem-bers (91.5％),and CAM users had significantly more knowledge and more positive attitudes toward CAM therapies than nonusers.Among users,66％ said they would not follow their healthcare providers\' instructions to not use CAM therapies,and 69.5％ said they would not disclose their plan to use CAM ther-apies with their healthcare provider.Neither demographic nor clinical characteristics were associated with CAM use.The factors that best predicted the use of CAM therapies were their availability and low cost (odds ratio[OR]=4.59;95％ confidence interval[CI]:3.01-7.01),the belief that CAM therapies were safe (OR-2.04;95％ CI:1.40-2.95),the belief that CAM therapies could help with diabetes control(OR =1.75;95％ CI:1.15-2.66),and the belief that CAM therapies could help maintain physical health(OR =1.68;95％ CI:1.13-2.49).Conclusion:CAM therapy users were more knowledgeable and had more positive attitudes toward CAM,but most of them chose not to disclose their CAM use to their healthcare providers.CAM use in Indonesia was associated with its accessibility,affordability,safety and effectivity,but not with any demographic or clinical characteristics.This study provided new evidence and insights for nurses and physicians in Indonesia that will help to design educational programs about the safety and efficacy of CAM therapies.