Albrecht Kossel, German physician and biochemist, Nobel Prize laureate (d. 1927)
Ludwig Karl Martin Leonhard Albrecht Kossel (German pronunciation: [ˈalbʁɛçt ˈkɔsl̩] (listen); 16 September 1853 – 5 July 1927) was a German biochemist and pioneer in the study of genetics. He was awarded the Nobel Prize for Physiology or Medicine in 1910 for his work in determining the chemical composition of nucleic acids, the genetic substance of biological cells.

Kossel isolated and described the five organic compounds that are present in nucleic acid: adenine, cytosine, guanine, thymine, and uracil. These compounds were later shown to be nucleobases, and are key in the formation of DNA and RNA, the genetic material found in all living cells.

Kossel was an important influence on and collaborator with other important researchers in biochemistry, including Henry Drysdale Dakin, Friedrich Miescher, Edwin B. Hart, and his professor and mentor, Felix Hoppe-Seyler. Kossel was editor of the Zeitschrift für Physiologische Chemie (Journal of Physiological Chemistry) from 1895 until his death. Kossel also conducted important research into the composition of protein, and his research predicted the discovery of the polypeptide nature of the protein molecule.

The Albrecht Kossel Institute for Neuroregeneration at the University of Rostock is named in his honor.