Folic acid has been chosen as the tumor-targeting molecule (TTM) in our ongoing studies on tumor-targeting drug delivery systems. Folate receptors are overexpressed on many types of cancer cells making these receptors an attractive target for delivery of cancer drugs. We have designed a folate-taxoid conjugate to target these tumor cells specifically. SB-T-1214, a highly potent second-generation taxoid was chosen as the cytotoxic drug. This drug was conjugated to folic acid through a novel disulfide linker developed in our laboratory and a PEG-spacer. Upon internalization into the tumor cell the potent taxoid will be released from the conjugate by the action of glutathione present in the tumor cell. The synthesis and study on the internalization using the fluorescence-labeled conjugate will be presented.