A high proportion of global coverage by protected areas is composed of relatively few very large protected areas (vLPAs); it is therefore important to understand their contribution to biological conservation. Here, using fresh analyses and a review of literature, we examine five particular contentions about existing terrestrial vLPAs: that they (1) are highly biased in environmental coverage, (2) contain low numbers of overall and rare species, (3) make limited contributions toward meeting global conservation prioritization schemes, (4) contain substantial areas of wilderness, and (5) are relatively immune to threatening processes. These contentions are generally supported. The principal contribution of vLPAs is substantial global coverage of wilderness, and more broadly, of areas where human influence is much reduced. There is also some evidence that individual vLPAs can retain unusually intact species assemblages and significant populations of particular species of regional or global conservation concern, and they can have marked regional conservation significance. The current level of threat to many vLPAs, and the challenges for their management, therefore are substantive concerns.