OBJECTIVE: Although the use of complementary and alternative medicine (CAM) by the general population has been surveyed previously, the provision of CAM by Japanese physicians in private clinics has not been studied. Universal health insurance system was established in Japan in 1961, and most CAMs are not on the drug tariff. We aimed to clarify the current status of CAM provided by physicians at private clinics in Japan. METHODS: We conducted an internet survey on 400 directors/physicians of private clinics nationwide on the provision of CAM from February 6 to February 10, 2017. Survey items included attributes of subjects, presence/absence of sections or facilities for provision of CAM, proportions of health insurance coverage for medical practices, and source of information. Private clinic was defined as a clinic run by one physician, with less than 20 beds. RESULTS: Commonly provided CAMs were Kampo (traditional Japanese herbal) medicines (34.8%) and supplements/health foods (19.3%). CAMs on the drug tariff were provided in 46.5% of cases at the clinics, but only 16.5% of cases were provided CAMs which were not on the drug tariff, at different neighboring facilities. Among different specialties, Kampo medicines were prescribed at obstetrics/gynecology (54.0%), orthopedics (44.4%), and dermatology (43.0%). Clinics not providing any CAM accounted for 53.5%. With regard to health insurance coverage, 96.8% of the clinics provided only or mainly health services on the universal national health insurance tariff (29.8% and 67.0%, respectively). CONCLUSION Kampo medicines represent the most commonly used CAM in private clinics in Japan, and universal national health insurance coverage is considered to be the reason for the high rate of their use.