The Department of Biological, Geological, and Environmental Sciences (BGES) at Cleveland State University was formed in July, 1997, by the merger of the Department of Biology and the Department of Geological Sciences. It is one of the founding Departments of the College of Science.

The Department offers a wide range of instruction in the fields of Biology, Geology, and Environmental Science. It offers BS and BA degrees at the undergraduate level, as well as MS degrees in Biology and in Environmental Science, and a PhD in Regulatory Biology. Students at both undergraduate and graduate levels have the opportunity to carry out research in conjunction with faculty, as well as independent study in areas of their own interest, and to take a wide range of formal courses. Together with adjunct researchers at the Lerner Research Institute of the Cleveland Clinic, the department has a strong focus on basic research in molecular and cell biology as related to biomedical questions. A second major research focus is on the physical and biological aspects of the environment and ecology of the region.