Standard prerequisites for graduate work in biology include two years of chemistry, two years of biology (including biochemistry and microbiology), one year of physics, and one year of calculus. Students admitted to the department with a deficiency take the required courses during the first year of graduate work. Applicants must include results of the Graduate Record Examination, preferably including an advanced test in one of the biological sciences.

The purpose of the Ph.D. program in clinical Laboratory Science is to prepare individuals to assume positions as directors of clinical laboratories, researchers, or as faculty of medical technology programs. Students first receive a broad background in basic sciences, biomolecular sciences, and clinical laboratory sciences, and then proceed to specialize in clinical chemistry, clinical microbiology, or clinical immunology. Students may complete their dissertation research in the Department of Biology at Catholic University or at one of the affiliated hospitals or research institutions, including the National Institutes of Health, Children's National Medical Center, George Washington University Medical Center, Washington Hospital Center, and others. After receiving a broad science background, as described above, students in the M.S. Program specialize in education, laboratory management, or research. Applicants must submit results of the Graduate Record Examination and scores of a medical technology certification examination. The School of Library and Information Science and the Department of Biology offer a joint master's program (contact the Department of Biology for further details). The Center for Advanced Training in Cell and Molecular Biology was established in the Department of Biology as a national center to provide expert training for scientists and technicians. Its primary emphasis is on intensive, three to five-day lecture/laboratory programs which focus on new biomedically related concepts and technologies. The Institute for Biomolecular Studies fosters biological research by faculty, students, and associates.

The Department of Biology accepts both full-time and part-time graduate students. In addition to the thesis options described above, a non-thesis option is available at the M.S. level. Applications from women and minority students are encouraged for all programs. Financial aid is available as university scholarships, teaching assistantships, and research assistantships.