In Model Driven Development (MDD), models replace software code as the development artifact. At the same time, requirements represent the information that is elaborated in models. However, despite the tight relationship between models and requirements, only a few MDD approaches provide the necessary methodological guidelines and tool support to explicitly facilitate this relationship. We analyze approaches for integrating requirements with models within MDD and highlight the common characteristics, benefits, and problems. Based on the analysis, we elicit a set of general properties that need to be fulfilled when considering the integration of requirements and models, and we assess the contribution of the considered approaches accordingly.