Events of the past decade haveunderscored the vital need for social safety net (SSN)programs in all countries, especially in times of crisis.Many countries have some form of targeted SSN program,especially in high- and middle-income countries, but SSNsare increasingly spreading to the lowest income countries.Over fiscal years 2000-10, the World Bank supported SSNswith $11.5 billion in lending and an active program ofanalytical and advisory services and knowledge sharing, muchof it during the last two years of the decade in response tothe food, fuel, and financial crises. Yet the crises alsopointed out weaknesses, as many middle-income countries(MICs) found that their poverty-targeted SSNs were notflexible enough to increase coverage or benefits as needed,and low-income countries (LICs) lacked poverty data andsystems to target and deliver benefits. Bank support evolvedin positive directions over the decade. The Bank began tomove from a project-focused approach that emphasizeddelivery of social assistance benefits toward an approachthat focused on helping countries build SSN systems andinstitutions to respond better to poverty, risk, andvulnerability. Stronger demand for SSN support in MICs ledto significantly stronger engagement there than in LICs.However, the recent crisis-related expansion of supportincluded also LICs and permitted initiation of Bank supportin 15 new countries. The Bankapos;s support to SSNsthroughout the decade has relied strongly on both lendingand knowledge sharing to engage clients. Bank support haslargely accomplished its stated short-term objectives andhelped countries achieve immediate impacts. But to achievethe longer-term goal of developing country SSNs, short-termobjectives need to be better defined, effectively monitored,and anchored in a longer-term results framework. Weaknessesin poverty data, program designs, and monitoring indicatorsneed to be addressed to ensure target groups are adequatelyreached. The Bank made substantial progress over the decade,but key areas of Bank support need strengthening.