The increasing industrial acceptance of cloud-based IT services has led to a paradigm shift in the development and operation of complex business applications. IT managers are incorporating cloudbased IT services as replacements and/or as enhancements for existing on-site solutions. This strategy leads to the concept of a federated business application, which consists of a variety of on-site and cloud-based subparts, dynamically orchestrated to a single solution. In this setting, the selection of appropriate IT services is critical. Following the discussions of environmental thinking in IT aspects like Green IT and Green IS, the issue of appropriate IT service depends on not only functionality and costs, but additionally also on the environmental impact of the service selection. To address this issue, this paper presents a service selection model for cloud-based services with a focus on the environmental aspects of the selection process. This is done by modeling a multi-criteria decision model based on the rational choice theory. The proposed model provides a selection process which leads to maximal service functionality coverage with minimal environmental impact for a given service provider setting. The application of the model is illustrated in a typical industry case.