The goal in this research is to obtain some stylize facts about the nature of monetary and fiscal policies in Iranian economy. Different economic and political factors are selected as the potential explanatory variables in monetary base (MB) and government expenditure (GE) regressions and the posterior inclusion probabilities are calculated using a Bayesian model averaging approach. The results show that oil revenue is dominant in GE variations, GE and MB are not sensitive to output variations of different sectors, GE is not sensitive to a change in inflation, MB increases when inflation rises and MB growth rate is higher in average during 2005-2010 period. Therefore, it seems that the policy makers respond to a change in output and prices are not consistent with the macroeconomics recommendations and the economic attitude of the president is more effective. Keywords: Monetary Policy, Fiscal policy, Oil Revenue, Inflation, Output Growth, Bayesian Model Averaging JEL Classification: C11, O04, E62, E52