A method and information processing system manage workflow instance migration. An initial workflow process model is compared with a new workflow process model. A set of differences between the initial workflow process model and the new workflow process model are determined. At least one set of activities associated with the initial workflow process model that is migrateable to the new workflow process model is identified based on the set of differences. A migration plan associated with the initial workflow process model and the new workflow process model is generated. The migration plan includes the at least one set of activities associated with the initial workflow process model. The migration plan is then used to evaluate a set of workflow instances associated with the initial workflow process model and migrate one or more of these workflow instances to the new workflow process model based thereon.