Abstract: The INTEGRAL mission is aimed to the fine spectroscopy and fine imaging of celestial gamma-ray sources with concurrent source monitoring in the X-ray and optical energy ranges. The mission will be controlled from the INTEGRAL Mission Operation Centre (MOC) at ESOC in Darmstadt, based on scientific utilisation planning inputs provided by the INTEGRAL Science Operation Centre (ISOC) located at ESTEC (Nordwijk-NL). The satellite science data will be processed at INTEGRAL Science Data Centre (ISDC) in Versoix (CH). This paper describes the IMCS components from the design and integration point of view. It aims to provide readers with an understanding of how a combination of in-house developed software systems (SCOS-2000 Software infrastructure) complemented by specific additional development and by the adoption of Commercial Off-The-Shelves (COTS) products is best suited to fulfil the operational user requirements of a complex and demanding real-time critical system.