: This paper presents a framework for assessing inter-organizational integration of business information systems. The framework is organized along two dimensions, intensity of integration and flexibility of integration. Intensity of integration describes the extent and strength of IS integration. It may be used as an indicator to assess the degree to which integration objectives can be achieved. Flexibility of integration denotes the ease with which integration implementations can be redesigned and collaborating partners can be replaced by other organizations. We specify these dimensions with relevant integration criteria.