Identifying and fulfilling adult learners' needs is critical to instructional designs aimed at enhancing their achievement and self-empowerment. In reviewing different theories and perspectives on adult learning and online and blended learning (OBL), it is noteworthy that there is not a comprehensive framework to guide the design of OBL environments that meet adult learners' needs, and that are underpinned by adult learning theories, online knowledge construction, motivational theories, and technological acceptance models. In this respect, the theory of existence, relatedness, and growth (ERG) (Alderfer, 1972) is applicable to interpret different types of needs to sustain learning motivation. Employing the ERG theory as the overarching framework, the purpose of this paper is to capture adult learners' needs from both positivist and subjectivist perspectives. In other words, the identified needs are to help adult learners optimally perform the learning activities designed to achieve the learning goals on the one hand, and to sustain their motivation during the learning process on the other hand. Thus, the framework is helpful for practitioners, curriculum developers, and researchers who are in search of a theoretical background for both instructional design and empirical investigation.