The present invention provides a method for treating cancer. The method involves the administration of an HSP90 inhibitor and an antimetabolite, where the combined administration provides a synergistic effect. In one aspect of the invention, a method of treating cancer is provided where a subject is treated with a dose of an HSP90 inhibitor in one step and a dose of an antimetabolite in another step. In another aspect of the invention, a method of treating cancer is provided where a subject is first treated with a dose of an HSP90 inhibitor and subsequently treated with a dose of an antimetabolite. In another aspect of the invention, a method of treating cancer is provided where a subject is first treated with a dose of an antimetabolite and subsequently treated with a dose of an HSP90 inhibitor.