Carrying capacity, or the maximum potential population in a particular environment, has been an attractive concept for grasping human-environment relationships. This concept is expected to predict the future potential for human survival in rural areas of developing countries, taking sustainable development parameters into account. Since there are various problems in applying the carrying capacity to the real situations, however, revisions and additions to the conventional concept are apparently needed. Based on empirical information from Papua New Guinea communities, this paper aims to criticize the concept and proposes some alternations to it.