One of the fundamental tenets of fiscal federalism is that, absent various sorts of externalities, decentralized governments that rely on own-source revenues should be more fiscally efficient than decentralized governments that rely on grant financing. The argument relies in part on the idea that sub-national governments, being closer to the people, are more accountable to its citizens. Accountability to citizens is also important in understanding the presence of corruption in government. This suggests that the financial structure and institutions of decentralized governments can potentially influence the degree and extent of corrupt activity. Financial structures that make governments more accountable should be associated with less corruption (other things equal), while financial structures with less accountability should be associated with more corrupt activities. We develop a simple model in which the use of grants rather than locally raised taxes increases corruption. We then use a panel data set of Mexican states to study the relationship between funding sources for Mexican states and the level of corruption in those states. We find that greater use of own tax revenues lowers corruption while greater use of grants increases corruption. This suggests that expenditure decentralization that is accompanied by revenue decentralization is likely to discourage corruption while expenditure decentralization that is funded by grants tends to encourage corruption. We also find that poverty, a measure of uninformed citizens, leads to greater corruption.