Provided are a method, system, and program for utilizing a virtualized data structure table such as an address translation and protection table (TPT), for example, in an I/O device. The virtualized data structure table has virtually contiguous data structures but not necessarily physically contiguous data structures in system memory. The data structure table may be accessed in a virtually contiguous manner. In the illustrated embodiment, the table is subdivided at a first hierarchal level into a plurality of virtually contiguous units or segments. Each unit or segment is in turn subdivided at a second hierarchal level into a plurality of virtually contiguous subunits, subsegments, pages or blocks. Each page or block is in turn subdivided at a third hierarchal level into a plurality of physically contiguous table entries. The data structure table may be accessed in a virtually contiguous manner utilizing a set of hierarchal data structure tables corresponding to the hierarchal levels of the data structure table.