This paper proposes a new approach to solve robust $H{infty}$ control problems for uncertain continuous-time descriptor systems. Necessary and sufficient conditions for robust $H{infty}$ control analysis and design are derived and expressed in terms of a set of LMIs. In the proposed approach, the uncertainties are allowed to appear in all system matrices. Furthermore, a couple of assumptions that are required in earlier design methods are not needed anymore in the present one. The derived conditions also include several interesting results existing in the literature as special cases.