The objective of this study was to evaluate the use of complementary and alternative medicine (CAM) and related factors among patients with chronic diseases. A cross-sectional study was carried out in outpatient clinics of a general hospital using a random sample of 252 adult patients with chronic diseases. Data included information on patient demographics and socioeconomic factors, as well as items to identify CAM use and the reasons for using CAM. Data were evaluated by Pearson's chi(2)-test and Fisher's exact test. It was found that 55.9% of study patients applied CAM. A significant number of patients (63.8%) were using CAM for hypertension. This study found that CAM use was associated with female gender, married status, housewives, low income and high levels of education. The present study confirmed the high frequency of CAM use among patients with chronic diseases in a Turkish public hospital.