Conceptual Research - a non-empirical research method- is among the three most used research methods in the discipline of Information Systems. However, its principles and foundations are implicitly used by researchers. Thus, its importance for advancement and development of the IS discipline is underestimated when it is compared with empirical research methods. In this research article, we develop the case for conceptual research. For this aim, we first review the main IS research method taxonomies reported in IS literature, and an integrative framework of IS research methods, based on Theory of Systems is developed. Second, we explain the place and relevance of the conceptual research method in this new framework. Finally, we illustrate the framework’s usefulness with four exemplary research papers reported in top IS journals.