Methods for treating proliferative disorders, by administering reovirus to a ral-mediated proliferative disorder, are disclosed. The reovirus is administered so that it ultimately directly contacts target cancer cells. Proliferative disorders include but are not limited to neoplasms. Human reovirus, non-human mammalian reovirus, and/or avian reovirus can be used. If the reovirus is human reovirus, serotype 1 (e.g., strain Lang), serotype 2 (e.g., strain Jones), serotype 3 (e.g., strain Dearing or strain Abney), other serotypes or strains of reovirus, and recombinant reovirus can be used. Combinations of more than one type and/or strain of reovirus can be used, as can reovirus from different species of animal. Either solid neoplasms or hematopoietic neoplasms can be treated.