A synoptic edition of the English version of John Arderon’s De judiciis urinarum containing the commentary on Giles of Corbeil’s Carmen de urinis as preserved in Glasgow University Library, MS Hunter 328, from the early 15th century, and Manchester University Library, MS Rylands Eng. 1310, from the 16th century. The English version of De judiciis urinarum is a detailed uroscopic treatise instructing the mediaeval practitioner on the examination of urine with twenty colours and eighteen to nineteen contents, incorporating colour descriptions, diagnoses, medicines and information about urinary contents. The present edition offers the semi-diplomatic transcription of these hitherto unedited texts, accompanied by a glossary, notes and introduction, the latter containing the textual transmission of the text, a codicological/palaeographic description together with the analysis of the scribal language. The present edition will be useful as a primary source for research not only in Historical Linguistics but also in other related fields such as the History of Medicine or Ecdotics.