The processing of a task on a machine often requires an operator to setup the job. In this paper we consider the problem of scheduling a finite set of jobs on a number of identical parallel machines. Each job has a setup that must be performed by an operator, who can perform only one setup at a time. We examine the problems of minimizing the schedule makespan. Out results include complexity proofs, special cases that can be solved in polynomial time, lower bounds, and approximation algorithms with error bounds.