Tax, the greatest source of revenue of a country, has a significant influence for the government as well as the welfare of its citizens. An increase in the level of tax compliance, meaning there are more citizens as taxpayers who comply to their tax obligations, will increase a country’s revenue. However, the data gathered from KPP Pratama Medan Polonia itself show the fluctuations of tax compliance percentage within the past five years. The purpose of this research is to find out the influence of taxation system and tax sanction towards the compliance of individual taxpayers at KPP Pratama Medan Polonia. This research is a survey research conducted by distributing questionnaires as the data collection instrument with the sample of 100 individual taxpayers at KPP Pratama Medan Polonia. Likert scale ranging from 1 to 5 is applied in assessing each item in the questionnaires. Regression test results show that both taxation system and tax sanction partially influence the compliance of individual taxpayers at KPP Pratama Medan Polonia. The results also show that both taxation system and tax sanction simultaneously influence individual taxpayers’ compliance. The variable independents’ influence can be seen from the value of coefficient determination (R2) which is 0.269 or 26.9 percent, indicating the correlation among taxation system and tax sanction towards the individual taxpayers’ compliance at KPP Pratama Medan Polonia, while the remaining 73.1 percent is influenced by other variables.