The effects of exogenous short-chain ceramide (1) on the arrest of growth of cancer cells in vitro and induction of apoptosis have been well documented. In the present study, an analog of 1 with a disulfide linkage, N-(4',5'-dithiaheptanoyl)-D-erythro-ceramide (2), was synthesized and found to be significantly more antiproliferative and cytotoxic than 1 in BT549, A549, and DU145 cancer cells. The activity was correlated with a reduction in cellular glutathione (GSH) level. Ceramide analogs with a tri- and tetra-sulfide moiety were also prepared, but they did not deplete cellular GSH levels and did not possess antiproliferative or cytotoxic properties.