This work was conducted to identify pollution and its impact on human and fish health, as well as to investigate the most important diseases in both humans and fish caused by pollution. It provides an overview of the main types of environmental pollution and their effects on health. Special attention is given to fish diseases resulting from pollution, including those of biological, physical, and chemical origin, along with issues related to aquatic environment pollution. For human health, the focus is on diseases caused by water, soil, and air pollution. The study also addresses sewage water and the fate of pollutants. In conclusion, this book aims to contribute to the dissemination of knowledge and to support scientific progress in Iraq.