Complementarities between infrastructure projects have been understudied. Our paper examines interactions in the impacts of large-scale road construction, electrification, and mobile phone coverage programs in rural India. We find strong evidence of complementary impacts between roads and electricity on agricultural production: dry season cropping increases significantly when villages receive both, but not when they receive one without the other. These complementarities are associated with a shift of cropping patterns towards market crops and with improved economic conditions. In contrast, we find no consistent evidence of complementarities for the mobile coverage program.