In the face of continuing development challenges in the world's poorest countries, there have been new calls throughout the donor community to increase the volume of development aid. Equal attention is needed to reform of the aid business itself, that is, the practices and processes and procedures and politics of aid. This paper sets out the shortcomings of that business on which new research has recently shed light, but which have not been adequately or explicitly incorporated into the donor community's reform agenda. It outlines seven of the worst "sins" or failings of donors, including impatience with institution building, collusion and coordination failures, failure to evaluate the results of their support, and financing that is volatile and unpredictable. It suggests possible short-term practical fixes and notes the need ultimately for more ambitious and structural changes in the overall aid architecture.