This paper addresses the impact of aid supply on aid effectiveness. First, we review theoretical literature that deals with the problem of governance in donor-recipient relationships and are susceptible of highlighting effects of aggregate aid availability. Second, we provide a conceptual framework that explicitly incorporates a trade-off between considerations of needs and governance. We examine the impact of aid supply on the manner in which a donor agency allocates the available money between countries differing in terms of both needs and domestic governance. The central conclusion is that a donor's utility function that embodies the need-governance trade-off and the associated optimization mechanism yield a meaningful rule to guide inter-country allocation of aid resources.