Water pollution by organic and/or inorganic pollutants has gained considerable attention all over the world. In the past decades, adsorption has been proposed as one of the most effective and simplest approaches to remove pollutants from contaminated waters, and polymer-based adsorbents have been widely used as efficient adsorbents except for activated carbon. Here, we reviewed recent patents on preparation of polymeric adsorbents and their derivatives as well as their application in pollutants removal from waters. Here, we classify the polymer-based adsorbents as four types for review: polymeric porous adsorbents; their chemically modified derivatives, polymer-coated inorganic hybrid adsorbents, and polymeric chelating adsorbents. Some of the features on their preparation, properties, and applications were illustrated by case studies. The forthcoming development in the given field was also discussed.