This chapter discusses the fuel blending technology, management of a blending project, many important topics such as linear and nonlinear blend models, methods to handle blend nonlinearity, concepts of recipe optimization and planning process in a refinery, etc. After the fundamental concepts are reviewed, the chapter discusses the design aspects of a blending project for the automation of field equipment and instrumentation, hardware and software, and blending tank quality measurement. The chapter concludes with methodologies to estimate various sources of errors and assesses the current state of blending state and successful implementation of upgrade or revamp of a blending system.