This paper studies the reliable H-infinity control for linear time-invariant multiparameter singularly perturbed systems against sensor failures. By time-scale decomposition, the full-order system is decomposed into slow and fast subsystems. After designing a reliable H-infinity controller for the global system, three reduced reliable H-infinity sub-controllers based on the slow and fast problems are obtained through the manipulation of the algebraic Riccati equations. The resulting control systems are reliable in that they provide guaranteed asymptotic stability and H-infinity performance when all control components are operational as well as when sensor failures occur.