The basic building blocks of a workcell are workstations, workers, machines, and means for holding and transferring items between workstations. This chapter begins with the assumption that product or part families exist, and that the combined volume of products in the family justifies dedicating machines and workers to focused workcells. It looks at cellular manufacturing applications, workcell design, and how workcells function individually and as elements of pull production systems. There are two fundamental kinds of workcells: assembly cells and machining cells. Workcells can be used to manufacture products that are more complex and involve numerous operations, such as small electronic devices and communications equipment. The chapter addresses worker staffing, equipment availability, and organizational and behavioral issues of workcell implementation. Changing the number of workers alters not only workcell capacity but also the unit manufacturing cost of the cell. Workcell productivity improvement is aimed at achieving the required cycle time with the minimum number of workers.