OBJECTIVES: To evaluate the prevalence and patterns of CAM use among cancer patients in Malaysia. In addition, the study focuses on the perceived effectiveness of CAM over conventional therapies, information seeking behaviour and CAM disclosure to health care providers. METHODS: The study was designed as a questionnaire based, cross sectional analysis. A prevalence based sample of 393 cancer patients attending the oncology clinics at Penang General Hospital was hereby selected for the study. Adult patients (18 years old), having diagnosed with cancer (any type), able to read or understand Malay (national language of Malaysia) or English language were recruited between August to November 2011. RESULTS: Overall, 393 questionnaires were completed and included in the analysis, showing that 46.1% of cancer patients had used CAM, with most (57.6%) believing that CAM therapies assisted the body’s natural forces to heal. CAM usage was significantly associated with gender (P=0.021), level of education (P=0.001), employment status (P=0.02) and monthly income (P<0.001). Among the frequently used CAM were biologically-based therapies including nutritional supplements (used by 75.5% of the participants). Friends and family members were the most common source of CAM information (for 75.5% of the participants). Only 13% reported side effects from using CAM. CAM use disclosure to the doctors was 43%; however, doctors had specifically asked about CAM use in 33.4% of the cases. The most common reason given for non-disclosure was ‘it is not important for the doctors to know about CAM use (34.2 %). CONCLUSIONS: Cancer management and treatment requires compliance to effective therapies at early stages. Health care providers should engage cancer patients in an open non-judgmental dialogue to ascertain better understanding of cancer and its treatment options.