Despite the existence of several methods and tools for engineering products and services, the Product-Service Systems (PSS) design field still lacks some pragmatic support. This paper assumes the existence of a gap between the existing approaches and logics used in product and service engineering that challenges the product-service integration in PSS design. To better support product-service integration in PSS, this paper proposes a system-based conceptual framework for PSS engineering. The framework is based on a system concept that defines products and services as ‘subsystems’ sharing similar properties. The conceptual framework supports the PSS design progression process by integrating and coupling product and service engineering viewpoints. Its aim is to support the engineering process of an entire system until reaching the most detailed phases. The main point of interest of the proposed approach is the specific light it shines on product and service engineering logics and its ability to unify disjoint definitions and processes by proposing a communication basis via a system-based framework.