We consider the model-checking problem for sequential programs with procedure calls. We first present basic algorithms for solving the reachability problem and the fair computation problem. The algorithms are based on two techniques: summarization, which computes reachability information by solving a set of fixpoint equations, and saturation, which computes the set of all reachable program states (including call stacks) using automata. Then, we study formalisms to specify requirements of programs with procedure calls. We present an extension of Linear Temporal Logic allowing propagation of information across the hierarchical structure induced by procedure calls and matching returns. Finally, we show how model checking can be extended to this class of programs and properties.