Strategic purchasing in healthcare is an approach for optimizing resource use, improving service quality, and promoting equity within health systems. While extensive literature exists detailing various aspects of strategic purchasing in healthcare, this chapter is specifically designed to address the unique perspectives and needs of health insurers, providing tailored insights and strategies to optimize purchasing decisions in alignment with insurer objectives. This chapter explores the core principles and mechanisms of strategic purchasing, addressing its significance in the context of rising healthcare costs, variable service quality, and the need for sustainable health financing. Strategic purchasing centers on three fundamental domains: what to purchase, from whom to purchase, and how to purchase, all of which are discussed with respect to maximizing value and aligning with population health needs. In addition, in this chapter we bring an additional fourth domain of monitoring and evaluation and use of data for improving the efficiency of the health system. Key strategies, such as selective contracting, value-based purchasing, and performance-based incentives, enable health insurers to establish efficient provider networks and promote high-quality care. The chapter also examines the role of stakeholders, including health insurers, healthcare providers, regulatory bodies, and the public, in creating an environment that supports effective strategic purchasing. The chapter also describes how the cost evidence plays a pivotal role in strategic purchasing by enabling health insurers to design benefit packages, set provider payment rates, and make informed purchasing decisions that balance quality with financial sustainability. By utilizing a variety of payment mechanisms such as capitation, bundled payments, and risk-sharing agreements-insurers can drive cost-effectiveness, encourage preventive care, and support financial sustainability.