This paper addresses the static and integral output feedback stabilization problems of continuous-time linear systems with an unknown state/input delay By combining an augmentation approach and the delay partitioning technique criteria for static and integral output feedback stabilizability are proposed in terms of nonlinear matrix inequalities with a free parameter matrix introduced These new characterizations possess a special structure which leads to linearized iterative computation The effectiveness and merits of the proposed approach are shown through numerical examples (C) 2010 Elsevier Ltd All rights reserved