Polymer microarrays offer a high-throughput approach to the screening and assessment of a large number of polymeric materials. Here, we report the first study of protozoan-polymer interactions using a microarray approach. Specifically, from screening hundreds of synthetic polymers, we identified materials that either trap the waterborne protozoan parasite, Cryptosporidium parvum, or prevent its adhesion, both of which have major practical applications. Comparison of array results revealed differences in the adhesion characteristics of viable and non-viable C. parvum oocysts. Material properties, including polymer composition, wettability and surface chemistry, allowed correlation of binding and identification of structure function relationships. Understanding C. parvum binding interactions could assist in improved water treatment processes and the identified polymers could find applications in sensor and filter materials. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.