Thanks to their numerous letters, Pūšu-kēn’s Assyrian merchant family and their commercial activities with Upper Mesopotamia and Anatolia during the first half of the 19^th century before the common era are quite well known to us. Despite being over 1,200 km away from each other, Aššur and Kaneš – the main Anatolian kārum (trading post) – were tightly bound by a series of treaties between the crossed kingdoms and Aššur which monitored commercial flows through taxation and customs posts. Pūšu-kēn’s family often went back and forth between their hometown and Anatolia on donkey-backs to exchange tin and textiles for copper, silver or gold and some men even went as far as to settle there for several years. Despite being quite well established in the Old Assyrian system, Pūšu-kēn and his sons did not think twice about making the most of the state apparatuses’ weakness and often stepped out of the lines drawn by treaties to smuggle. The aim of this article is to study how the risky balance between law and fraud plays out in this family who embodies the dynamics of this long-distance trade. Their role in Old Assyrian trade will be analysed first before delving into the reactions of the powers that be and the consequences of these illegal acts on Pūšu-kēn’s family.