Community-based development projects are often argued to strengthen social capital. This paper investigates the impact of a women's empowerment program in India on trust and cooperation, using data on 2,000 households. The program significantly increases trust and stimulates contributions to educational and infrastructural community projects. The effect on informal assistance among households is less consistent. The findings suggest substantial spillovers on the wider community. Households who do not participate in the program themselves but who live in a program village are significantly more trusting and more likely to engage in collective action than households in control villages. © 2009 Elsevier Ltd.