Based on archival material from Russia’s State Archives of Ancient Acts (Siberian Prikaz), the present article analyses with full details the agricultural aspect of Russian colonisation in western Siberia during the seventeenth century. Considering the peculiar nature of this settlement process in a region characterised by a low density of population, it focuses on the way the Slav settlers organised their economic activities in relation with local authorities. Linked with defence requirements, the need for Muscovite administration to control peasant colonisation ran into land use regulations. After the transfer of the Siberian affairs to the Kazan Prikaz in 1599, Boris Godunov established the podmog system which obliged the voevods to provide new settlers with all the tools they could need (from spades to telegas with horses). Until the end of the seventeenth century there were several advantages for the arriving peasants to develop the state-required production. With the increase of internal migrations and the coming up of land rivalries, the local administration tried to tighten up its control. For instance, just after their arrival in the appointed places, peasant families were required to build permanent houses and not to move away. One of the most important achievements of the present article is to show with concrete examples the paradoxical effects of this settlement policy. More than individual land exploitation, a collective way of life was privileged by new settlers whose everyday practices were dominated by customary law. The state regulatory attempts were assessed, modified and applied with respect to the local situation and to the peasants’ interests. In such context, it was difficult for local authorities to secure the non-Russian populations’ rights. Unfortunately, the central question of the relations with autochthonous peoples is almost missing in this fascinating view on the chaotic colonisation of the Trans-Urals.