We developed an Agrobacterium-mediated leaf disk transformation method for chrysanthemum. We introduced a chimeric chalcone synthase (CHS) gene isolated from chrysanthemum into cv. Moneymaker (pink type) to produce white-flowered plants. The CHS coding sequence was in antisense or sense orientation relative to the CaMV 35S promoter. 3.6% (3/83) antisense-transformed plants and 1.5% (2/133) sense-transformed plants produced completely white flowers. Pigment analysis revealed that this was due to a block at CHS. To study stability of color change of the white Moneymaker plants. Moneymaker, a Moneymaker regenerant, an antisense white (2706),and a sense white (31435) were compared. There was no difference between Moneymaker and the regenerant. Both 2706 and 31435 were vegetatively propagated with good stability; all plants produced white or very pale pink flowers. 2706 flowered 7 days late and 31435 10-12 days late. Flower number was similar for all four lines tested.