In the annals of medieval medical as well as cultural history the name and authority of Hippocrates of Cos knows no rival other than his later disciple, Galen. Yet there has so far been no systematic attempt to gather together, with any degree of completeness, the names and locations of manuscripts of the individual treatises that circulated in the Latin West before 1500 under the name or aegis of the famed physician of Cos. The present investigation of this subject, that is of the constituents of a ‘Repertorium of Hippocratic Writings in Latin’ or of a ‘Hippocrates (Ypocras) Latinus,’ was begun nearly four decades ago, particularly in the ill-fated years 1938 to 1939, while on a sojourn in Europe before the outbreak of World War II. The intention, then as now, was to provide the basis for determining the extent to which there was continuity in the transmission of Greek medicine, albeit in Latin dress, from antiquity to the early and later Middle Ages. The research was thereafter continued sporadically whenever there was an opportunity to examine manuscripts in European depositories. In recent years the work has been greatly facilitated by the published results especially of the researches of two late scholars of medieval medical manuscripts, Augusto Beccaria and Ernest Wickersheimer, as well as by the cataloguing of various manuscript collections. However, there still remains the task of drawing out the individual works appearing under Hippocrates' name together with their commentaries, not only in the pre-Salernitan, but also in the succeeding centuries before about 1500. To this endeavor the present investigation is directed.