The present invention provides a method for treating cancer. The method involves the administration of an HSP90 inhibitor and an antimitotic, 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 antimitotic 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 antimitotic. In another aspect of the invention, a method of treating cancer is provided where a subject is first treated with a dose of an antimitotic and subsequently treated with a dose of an HSP90 inhibitor.