This briefing paper presents the findings from our research on the use of multi-sectoral needs assessments following the earthquake in Haiti in January 2010. It is one of two case studies that we conducted (the other being South Sudan) to examine how evidence on the scale and severity of humanitarian needs is generated and used by the humanitarian community in-country to formulate a response and quantify funding needs, and by donors to allocate funding. The paper analyses the first field-level implementation of the multi-sector initial rapid assessment methodology (IRA) and the use of its findings for the emergency response operation in the aftermath of the earthquake The desk study examined the process by which the Rapid Initial Needs Assessment for Haiti (RINAH) was carried out and analysed how the results were used by the main donors and by the cluster system in Haiti to guide their humanitarian assistance. The report also looks at the impact the use of the needs assessment had on the level of funding for the emergency. For donors and humanitarian organisations alike, the Haiti earthquake has been a difficult test of their readiness to adequately respond to a major natural disaster occurring in a capital city. In that sense, the decision to lead a large-scale multi-sector assessment in the initial stages of the emergency indicates an increasing awareness on the part of the humanitarian community of the need for a consolidated and commonly accepted analysis of needs and vulnerabilities of affected populations, from the outset of the humanitarian response. The use of cross-sector rapid assessments, such as RINAH, has the objective to provide timely, accurate and comprehensive information about vulnerability, needs, priorities and gaps while avoiding overlapping needs assessments. The proliferation of individual needs assessments by implementing agencies or donors, can be prejudicial for the purpose of humanitarian coordination and effective funding allocation as the methodologies vary and the data is not comparable. While the IRA pilot in Haiti was extremely challenging and didn’t fulfil all the expectations of the humanitarian community, it certainly was a major step in the right direction. The use of multi-sectoral initial rapid assessments must be supported and incentivised, but should be more strongly linked to the different elements of the response such as resource mobilisation, strategic decision-making and response planning.