Income smoothing is affected by some factors, one of these factors is political costs (PCs) which firms may pay to get information, trading, and negotiation which is imposed by the decision making and legislating authorities. Hence, the association between PCs and income smoothing is tested by focusing on Egyptian Stock Exchange (EGX), especially EGX 30, which included the most active firms, for a ten-year period from 2006 to 2015 for 63 firms, including 417 completed observations, the sample represented 10 different sectors. Two main hypotheses were formulated and tested, the first hypothesis consists of four sub-hypotheses, it was tested using multiple regression analysis, and the second hypothesis tested by testing the moderating effect of Egyptian revolution 2011 on the association between PCs and income smoothing. The findings are; first, PCs proxies have a positive and significant effect on income smoothing, second, there is a negative and significant moderating effect of Egyptian revolution 2011 on the association between firm size only and income smoothing.