Religious riots have complex underpinnings - frequently social, economic and political factors are involved. This paper demonstrates how these riots may influence voter behaviour and the incentives of political parties. Using data on Hindu-Muslims riots in India over 21 years, combined with electoral and demographic data, we demonstrate a causal link between[1] electoral politics and communal riots. We use an innovative instrument that draws upon the random variation in the day of the week that important Hindu festivals fall on each year to isolate the causal effect of riots on electoral results. We find that riots occurring in the year preceding an election increase the vote share of the Hindu nationalist Bharatiya[2] Janata Party in the election. Our results are robust to various robustness checks on the data and econometric analysis. This result does not imply that riots are not caused by electoral reasons. It may be the case that most of the riots are in fact the result of political calculations. Our attempt here is to disassociate those political reasons for riots and to examine the effect on electoral results of exogenously caused riots. The fact that our results show that a party systematically benefits from the riots, may establish that there is a clear incentive for this party to cause riots for electoral benefit. Therefore, our findings have important implications for the relationship[3] between ethnic violence and electoral politics not just in India, but also in other diverse democratic societies.