PURPOSE: To identify patients' report of complementary and alternative medicine (CAM) use, along with their knowledge, their attitudes, and their use/willingness to use CAM. METHODS: A total of 353 patients were recruited through a 'convenience' sampling method in four metropolitan hospitals in Adelaide. Data were collected by means of questionnaires with open- and close-ended questions. RESULTS: The prevalence of CAM use among patients was 90.4%; although a considerable proportion of patients using CAM did not disclose this information to nurses/doctors (39.9%) and 20.7% said they would report it as "only when needed/or if asked to". A high proportion of patients reported using non-herbal supplements (60.3%) and massage therapy (45%) while most forms of therapies were mainly used "only when needed". The CAM domain most frequently used was biologically based therapies (68.8%). Patients rated themselves as having "none" (24.4%) or "very little" (42.5%) knowledge about most CAM, although nearly half (46.4%) of them had a positive attitude towards CAM. Use, knowledge, and attitudes towards CAM were also associated with diverse socio-demographic variables. This study provides a comprehensive analysis of the use of CAM by patients.