Present studies were carried out to produce tetraploid plants by colchicine treatment using seeds, seedlings and shoot tips of Codonopsis lanceolata. Three tetraploid plants of C. lanceolata were produced from seeds which absorbed 0.1 % colchicine solution for 12 hours, and 0.5% colchicine solution for 1 and 6 hours from seedlings, respectively. But tetraploid was not produced from shoot tips treated by colchicine solution. Compared to diploid, tetraploid plants had larger stomata, but less number of stomata. Fresh weight of tetraploid plants was 1.4∼3.6 times heavier than diploid plants.