Supporting delegation mechanisms in workflow systems is receiving increasing interest from the research community. An important requirement of a constrained workflow is to guarantee the satisfiability of the workflow, which requires that some set of authorized users can complete a workflow. Typically, any mechanism that is used to establish the sat- isfiability of a workflow is based on the workflow specifica- tion and the user authorization information. The effect of a successful user delegation request is to change the user au- thorization information, thereby affecting the satisfiability of the workflow. Existing work on delegation in workflows does not con- sider the satisfiability of the workflow. In this paper, we address the satisfiability problem of workflows, while sup- porting user delegation mechanisms, in the context of three different workflow execution models. We consider delega- tion of concrete tasks, abstract tasks and roles. We present algorithms for evaluating various delegation requests in each workflow execution model.