ABSTRACT It is known to few that the path to the discovery of the long-denied plasma creatinine and its clearance was long and difficult. For quite a long time, related controversies between different groups of researchers were widespread and heated. The scientists who have dealt with the related problems are among the most famous of the last century and some of them are part of the history of medicine. Giovanni Ferro-Luzzi, an Italian clinician, was one of these researchers. He was among the first to detect and dose plasma creatinine and the first ever to measure the clearance of endogenous creatinine (CrCl). Unfortunately, due to a series of unforeseeable events, he has been completely forgotten together with his undertakings. In this review we retrace the steps that led to the measurement of plasma creatinine, and CrCl. With brief biographical notes we try to explain the oblivion of this important figure and of his nephrological accomplishments.