The purpose of this research was examining the effectiveness of income tax at the tax office in Demak. The Results of this study indicate that. The results of the overall income tax calculation is based on the planning and realisation of, where in 2009 the effectiveness of 105,5% is included in the category of highly effective, in 2010 the effectiveness of 107,1% which is very effective, in 2011 the effectiveness of 116,2 SL is very effective, and in 2012 the effectiveness of 96% which is effective. In 2009 the highest effectiveness level is income tax article 22 import of 266,26%, while the lowest is the income tax article 23 amounting to 67%. In 2010 the highest effectiveness level is the final income tax by 159%, while the lowest is the income tax fiskalluar the land of 0.05%. In 2011 the highest effectiveness level is income tax article 22 import of 212,13%, while the lowest is the income tax article 25/29 Private registration 63,85%. In 2012 the highest level of effectiveness is the fiscal income tax abroad amounted to 290,94%, while the lowest is the income tax article 23 amounting to 48,81%.