Computing a schedule for a given single machine problem is often difficult for irregular criteria, but when the data are uncertain, the problem is much more complicated. In this paper, we modify a genetic algorithm to compute robust schedules when release dates are subject to small variations. Two types of robustness are distinguished: quality robustness or robustness in the objective function space and solution robustness or robustness in the solution space. The modified genetic algorithm is applied to a just-in-time scheduling problem, a common problem in several industries.