The study was conducted to investigate the contamination of buildings and bathrooms with the fungus (Stachybotrys chartarum). 50 samples were taken from low-ventilation bathrooms that showed signs of contamination at the sample site, which was divided into public bathroom, school, hospital, old home, and modern home. 35 were isolated. An isolate of the S. chartarum fungus, with 10 isolates per site. The isolation rate from public bathrooms and old house was 100%, while it was 70% and 80% for school and hospital, respectively. While the isolates were 0 from samples taken from modern house, the isolates were subjected to test the phenotypic diagnosis, such as the variation in colony color and colony density, as well as the microscopic diagnosis, which included the color of the fungus under the microscope, the shape of the conidia, and the distribution of the conidia.