Abstract: Protoplasts isolated from petioles of sweet potato ‘Cenki’ and ‘White Star’ were cultured in the modified liquid MS medium containing 0.05 mg· L- 1 2,4-D and 0.5 mg· L- 1 KT. The first cell division occurred within 3 to 4 days. After 8 to 9 weeks of culture, small calli derived from protoplasts were placed on the solid MS medium supplemented either with 0.05-0.2 mg· L-1 2,4-D and 0-0.5 mg·L- 1 KT or with 0.5-2.0 mg·L -I NAA and 1.0-3.0 mg·L- 1 BAP for callus proliferation. Furthermore, the calli were transferred on to either the hormone-free medium or the medium supplemented with 2.0-3.0 mg· L- l BAP, followed by being transferred on to the hormone-free medium for plant regeneration. The frequency of protoplast-derived calli regenerating plants reached 60.0% in ‘Genki’ and 43.3% in 'White Star.