This paper presents results from recent liquid impact studies of a variety of glass and carbon fiber reinforced and nonreinforced thermoplastic and thermosetting polymers. Basic damage modes from single impacts in the velocity range 500 to 1000 m s_-1 are described and the mechanisms of failure are analyzed. The thermosetting resins studied are essentially brittle, in contrast to the very ductile thermoplastics, and these fundamental differences are emphasized when fibrous reinforcement is added. The effects of matrix properties, reinforcement geometry, the condition of the impacted surface, and impact angle are illustrated and discussed. The main conclusion is that, although no ideal solution exists to withstand all impact situations, it is possible to establish general rules which assist in the design of composites for specific purposes. In particular, reinforced thermoplastic resins are found to have considerable advantages over reinforced thermosetting resins for many practical situations, particularly when the postimpact material strength needs to be maximized.