This paper aims to explore the transformation in concepts and practices of debt existing in northern Sudan in the mid to late 19th century, focusing on the decades that led to the Mahdist uprising—a spectacular revolt which shook the Ottoman Empire and European colonial metropoles. From Muhammad Ali’s invasion of Sudan in 1820 until the Mahdist uprising, Sudan was formally under Ottoman-Egyptian rule. Whether this rule constituted “colonialism” in the European sense of the term has been subject to much debate. Such debates have largely focused on questions around Egyptian approaches to “race” in Sudan and, in particular, the issue of slavery. Building on this, my paper will consider how tracing changes in debt relations (and, relatedly, land) could contribute to our understanding of the nature of Ottoman-Egyptian colonialism in Sudan. It argues that Ottoman-Egyptian rule in Sudan changed over time, as the century progressed, particularly as Egypt found itself increasingly in debt to and subject to pressure by European financiers. Thus, my paper explores the ways in which Ottoman-Egypt’s indebtedness, particularly under the rule of Khedive Isma’il, influenced and arguably transformed its methods of governing and extracting resources from its “colony,” Sudan. This will be done in through focusing on two factors: first, changes in the ways in which taxes were extracted from the population (increasingly extracted in money and not in kind); second, the effect of the increasing alienability of land—leading to land dispossession when people fell in debt to the state for failure to pay taxes. In sum, my paper considers the extent to which the Mahdist uprising arose in the context of large-scale indebtedness and loss of land in northern Sudan—a change which served to undermine the “Islamic” legitimacy of Ottoman imperial or Egyptian rule in Sudan. In doing so, it seeks to foreground the role that debt plays across territorial boundaries—here, debt owed by Ottoman-Egypt to European creditors—focusing on its colonial nature and the forms of political-economic reorganisation, and resistance, it engenders.