Chrysanthemum stunt disease is one of the most serious diseases in chrysanthemum. In this study, possibility of contact transmission of Chrysanthemum stunt viroid (CSVd) through root was investigated. CSVd free chrysanthemum plants were cultured for three months in contact with the root of chrysanthemum plants infected with CSVd. As a result, CSVd was detected from 4.2-8.3% of CSVd free plants. Furthermore, when chrysanthemum plants were cultured in seedbeds more closely, the infection rate increased. CSVd was detected in 35-65% of chrysanthemum plants tested in the contact on and under the ground, 10-40% in the contact on the ground, and 10-20% in the contact under the ground. Injection of D-D or solarization was effective to prevent the infection of CSVd by killing plant roots.