The Microbiology department at the College of Medicine, University of Basrah and within the panel of discussions organised by the Microbiology department held a seminar presented by Dr. Ban Anas on the Blastocystis hominis . The research aims to study many aspects of Blastocystis, the most important of which is its prevalence rate and the most important methods used to diagnose the parasite and study its relationship with gastrointestinal diseases. Blastocystis hominis is an intestinal parasite common to humans around the world, a genus of single-celled parasites consisting of several species living in the gastrointestinal tracts of species as diverse as humans, farm animals, birds, rodents, reptiles, amphibians, fish and cockroaches. Blastocystis was initially classified as yeast, but later classified into the Sporozoa subcategory. The presence of human blastocystis hominis in the intestine may be asymptomatic and cause severe or chronic symptoms, due to pathogenic and non-pathogenic genotypes. Where many studies have been conducted in many Iraqi provinces regarding this parasite.