The application of a shoot tip culture to the problem of the multiplication of male sterile plants of Welsh onion was examined. Shoot tip explants of Welsh onion were grown on Murashige-Sko og medium containing various levels of kinetin and NAA under certain conditions. Formation of adventitious shoots or roots depended on the hormone levels used. Proliferation of adventitious shoots was the maximum in a medium containing Zmg/l kinetin and 0.5mg/l NAA. Moderate temperature (20°C) and long-day was optimal for adventitious shoot formation. Furthermore, formation of adventitious shoots was more active in explant isolated from stock plant which was more advanced in age. Adventitious shoots were rooted and grown into normal plants or were used to start new culture which formed more multiple shoots. The procedure for the transfer of the plantlets from nutrient media in aseptic containers to soil also was established. This technique will be useful for multiplication of male sterile plants of Welsh onion and the practical seed production of F, hybrid will become possible by applying this technique to the multiplication of female parent.