Background. This study aimed to identify the factors of CAM usage for general health and to determine the factors associated with the usage of different types of CAM after the diagnosis of chronic diseases among The Malaysian Cohort participants. Methods. This was a cross-sectional study derived from The Malaysian Cohort (TMC) project, a prospective population-based cohort aged between 35 to 65 years old that recruited from April 2006 to September 2012. Association between the CAM usage and contributing factors were determined via logistic regression. Results. The sample were mostly female (58.1%), Malays (43.1%), came from urban (71.9%), aged 44 years and below (26.8%) and had secondary education (45.9%). The prevalence of CAM usage varied across diseases; 62.8% in cancer patients, 53.3% in hypercholesterolemia, 49.4% in hypertensives and 48.6% in diabetics. General CAM usage was greater among female (OR: 1.54, 95% CI: 1.49, 1.59), Chinese (OR: 1.15, 95% CI: 1.12, 1.19), those with higher education (OR: 3.12, 95% CI: 3.00, 3.25), urban residents (OR: 1.55, 95% CI: 1.50, 1.61) and older people (OR ranging from 1.15 to 1.75) while for post-diagnosis of chronic diseases usage, the odds were higher among those with lower education and living in rural areas. Conclusion. Health status, educational level, age, living location and types of chronic diseases were significant factors that influence CAM usage for the intent of either health maintenance or disease treatment. Further exploration on CAM safety and benefit are crucial to minimize the adverse effect and to ensure the efficacy of CAM product.