In this chapter we treat problems governed by integrodifferential systems , . In Section 9.2 we present a version of the problems of interest and discuss existence. In Section 9.3 we specialize to systems linear in the state. In the next section we discuss linear systems and the bang-bang principle. In Section 9.5 we present a second version of the problem of interest. In Section 9.6 we discuss so-called linear plant quadratic cost criterion. We close the chapter by presenting minimum principle for a constrained problem governed by an integral equation.