This study was designed to measure the frequency at which Turkish patients with cancer resort to complementary and alternative medicine (CAM). A total of 704 patients referred to the Gülhane Military Medical Academy and Ankara Numune Training Hospital between September 2002 and January 2003 were asked about the CAM therapies they used. Of these, 276 patients (39.2%) had used CAM. Gender, marital status, educational status, age, financial status, severity of pain, history of cancer in the family, and their own ideas concerning CAM therapies were found to be correlated with the frequency of resorting to CAM. Resorting to CAM may lead to delayed diagnosis and treatment, adverse drug interactions, treatment withdrawal, and disease progression. Therefore, it is very important to inform patients about these potential dangers. Further studies are needed to clarify the reasons that lead patients to resort to CAM. © 2005 Lippincott Williams & Wilkins, Inc.