Desertion from is probably as old as the history of wars or interpersonal conflicts solved with by force, and despite changing civilisational and political circumstances and the way in which armed forces are organised, it is still present in the context of the functioning of the army. The Polish Army faced that issue as well, although the historians’ approach to the subject matter very often depended on their views on a given epoch. It is particularly noticeable in the works concerning the army of the Kingdom of Poland in the years 1815–1830, where all the issues regarding discipline were discussed from the point of view of “ruthless” and “brutal” methods of its execution used by Grand Duke Konstantin. In this article we try to look at the issue of desertion from a different perspective, namely in the light of documentation of military courts (of first and second instance), which tried soldiers accused of desertion. The records provide examples of how soldiers attempted to avoid military service and how they explained running away from their troops. What is more, they shed some light on particular stages of military court proceedings, the role of the prosecutor, and argumentation used by defence lawyers.