The H-2-optimal controller for systems with preview, in which the knowledge of external input is available in advance for the controller, is derived. The single input case is first considered and solved by transforming the problem into a non-standard LQR problem. Based on the single input result, the multiple inputs case and the multiple preview times case are treated. In every case considered, the controller consists of a static state feedback plus a finite impulse response block. The paper also provides a formula for the optimal H-2-norm that clearly shows how the performance gain owing to the previewed input varies as the preview time increases. (c) 2006 Elsevier Ltd. All rights reserved.