Large software systems are often deployed putting together many Commercial-Off-The-Shelf software components (COTS). The selection of the COTS to be integrated is driven by the software system requirements. In this paper, we propose the RECSS method aimed at supporting requirements elicitation and analysis in the context of COTS-based software systems. RECSS builds a goal model of the system environment which identifies the external elements that interact with it. Next, the system is decomposed into actors for which ISO/IEC-based
quality models are built. As part of the process, environmental and platform characteristics that influence the behaviour of the system are identified. Last, the resulting artefacts are used to analyse and refine the system requirements. 