The purpose of these guidelines is to establish greater understanding among all concerned about the different categories of protected areas. A central principle upon which the guidelines are based is that categories should be defined by the objectives of management, not by the title of the area nor by the effectiveness of management in meeting those objectives. The matter of management effectiveness certainly needs to be addressed, but it is not seen as an issue of categorisation.It is hoped that these guidelines will be used widely by those planning to set up new protected areas, and by those reviewing existing ones. They are designed to form a useful basis for preparing national protected areas systems plans. It is to be emphasized that these categories must in no way be considered as a 'driving' mechanism for governments or organizations in deciding the purposes of potential protected areas. Protected areas should be established to meet objectives consistent with national, local or private goals and needs (or amixture of these) and only then be labelled with an IUCN category according to the management objectives developed herein. These categories have been developed to facilitate communication and information, not to drive the system.These present guidelines, therefore, represent the culmination of an extensive process involving a wideranging review within the protected area constituency over a number of years. The opinions of those involved have been many. Some have recommended radical changes from the 1978 guidance; others no change whatsoever. Some have urged that there be regional versions of the guidelines; others that the categories be rigidly adhered to everywhere.The conclusion is guidelines which: adhere to the principles set forth in 1978 and reaffirmed in the task force report in 1990;- update the 1978 guidelines to reflect the experience gained over the years in operating the categories system;- retain the first five categories, while simplifying the terminology and layout;- add a new category;- recognise that the system must be sufficiently flexible to accommodate the complexities of the real world;- illustrate each of the six categories with a number of brief case studies to show how the categories are being applied around the world; and- provide a tool for management, not a restrictive prescription.