This collection of abstracts provides an account of four presentations at the 19th International Conference of the World Association for the Advancement of Veterinary Parasitology (WAAVP)(held in New Orleans, LA, USA from 10–14 August 2003) in a symposium session on zoonotic protozoan parasites found in the marine environment and chaired by Ronald Fayer and David Lindsay.The focus was on three genera of parasites of veterinary and public health concern—Toxoplasma,Giardia, and Cryptosporidium with emphasis on their epidemiology in the marine environment.