Background: Quantitative bibliometric measurements of research activity are frequently used, e.g. for evaluating applicants for academic positions. The purpose of this investigation is to assess research activity within the medical speciality of Clinical Biochemistry by comparing it with a matched control group from other medical specialities in Denmark., Materials and Methods: A list of all physicians registered in Denmark (23,127 persons) was drawn from the database "Laeger.dk". Of these, 5,202 were generalists (not included) while 11,691 were from other specialities. Of the 126 specialists from Clinical Biochemistry, 57 fulfilled the inclusion criteria. Each of these 57 was matched according to medical title with two randomly chosen specialists from other specialities, totaling 114. Using Medline and the Web of Science, the number of publications and the number of citations were then ascertained., Results: 25% of the 11,691 specialists held a PhD degree or doctoral degree, DMSci, (Clinical Biochemistry: 61%). The 171 specialists included in the study had 9,823 papers in Medline and 10,140 papers in the Web of Science. The number of Medline papers per specialist was 71 for Clinical Biochemistry compared to 51 for the control group. The number of citations per specialist was 1,844 for Clinical Biochemistry compared to 816 for the control group. The top ten H-indices (of which 8 were in Clinical Biochemistry) ranged from 30 to 69., Conclusion: Both the number of papers and the number of citations were higher for Clinical Biochemistry than for the control group. The difference was most pronounced among professors.