This chapter presents the modeling, identification and the motion control of serial robot manipulators with rigid and flexible joints. The perfectly rigid joint assumption, often at the basis of the study of manufacturing robots, can be insufficient in many situations. Flexible joint robots raise specific control issues, both in terms of static (deflections) and dynamic (vibrations) behavior. The chapter highlights the major differences compared to the perfectly rigid case and the characteristics related to flexibilities in modeling, identification and design of control laws. The reduced dynamic model of flexible joint robots is first recalled with its remarkable properties. Several identification approaches of this model are then presented and analyzed in terms of their implementation complexity and the instrumentation required by the experimental protocol. Finally, the chapter describes the main theoretical concepts and their application in several practical control strategies.