BACKGROUND: Eponyms are commonly used in medicine, but there are no specific studies of the use of eponyms in clinical chemistry. METHODS: Clinical chemistry eponyms were manually collected from books, review articles and journal articles from 1847 through 2020. Eponym usage was examined by searching titles and abstracts in PubMed. Custom Python scripts were used to first permute eponyms into multiple forms, and then to search PubMed using Biopython. The eponyms identified in PubMed were further focused on 2 clinical chemistry journals Clinica Chimica Acta [CCA] and Clinical Chemistry [CCJ]. RESULTS: The manual collection identified textgreater300 eponyms in clinical chemistry. The Biopython search of PubMed identified a subset of 97 unique eponyms in 33,232 articles. PubMed identified 26 eponyms used in 130 CCA articles; whereas a full- text search identified 1187 articles. In comparison, PubMed identified 36 eponyms used in 158 CCJ articles; whereas a full-text CCJ search identified 708 articles. PubMed shows that the journals CCA and CCJ had a peak number of eponym citations in 1977 followed by a steady decline. CONCLUSIONS: Eponyms have been frequently used in clinical chemistry with 97 eponyms in common use in PubMed. Overall, the use of clinical chemistry eponyms appears to be declining.