In this paper, tracking performance limitations for plants with input delay are considered. It is important to know the performance limitations for plants to design controllers and to design plants. Our objective is to find the fundamental limitation of the transient response in tracking control problem. When plant have input delay, no one would deny that tracking performance becomes worse than the plants without input delay. However performance limitations for such plants have not been derived analytically. We derive the performance limitations based on internal model control framework. The difference between plants with delay and without delay is compared by numerical examples.