This study is an attempt to examine the determinants of volatile discretionary public spending. Using a panel of 55 countries over the period of 1985-2012, first, we do the aggregate level analysis for the representative sample of the world. Onwards, we do the disaggregated analysis by decomposing the sample into developed and developing countries. By employing the Generalized Method of Moment (GMM), the results of the aggregate level show thatpolitical constraints on the executives, government stability, population and GDP growthsignificantly reduce discretionarly public spending volatility. However, the presidential system has a significant positive effect onit. In contrast, the results on the disaggregate level show that, in developing countries, the political constraints become insignificant while corruption becomes positively significant. Likewise, in developed economies, the presidential system and corruption becomes insignificantin affecting volatility. Supervisor:- Dr. Karim Khan