This paper approaches the problem of Luenberger-like observer design for a class of LTI discrete- time descriptor systems. We present and prove sufficient conditions for the observer design with a guaranteed decay rate where the admissible descriptor systems. In addition, assuming some standard controllability properties, a separation principle is demonstrated considering an observer-based output feedback control law. The observer design is also extended to cope with model disturbances in an H2 sense. The effectiveness of the proposed methodology is illustrated by numerical examples.