<p>We study the economic effects of the roll-out of mobile phone network coverage in rural South Africa. We address identifcation issues which arise from the fact that network roll-out cannot be viewed as an exogenous process to local economic development. We combine spatially coded data from South Africa's leading network provider with annual labor force surveys. We use terrain properties to construct an instrumental variable that allows us to identify the causal effect of network coverage on economic outcomes under plausible assumptions. We find substantial effects of cell phone network roll-out on labor market outcomes with remarkable gender-specifc differences. Employment increases by 15 percentage points when a locality receives network coverage. A gender-differentiated analysis shows that most of this effect is due to increased employment by women. Household income increases in a pro-poor way when cellular infrastructure is provided.</p>