Mercury in cigarettes of domestic and foreign products was measured by Magon's method, and the sample of a domestic brand was burned by a smoking machine and the smoke was collected for the measurement of mercury. In tobacco leaf and paper, only inorganic mercury was found in both domestic and foreign products. Its amount in tobacco leaf and paper of a piece of cigarette was about 60 ng in domestic products and about 30 ng in foreign products. By burning, the unit length of a cigarette released about 5-7 ng of mercury into smoke.