The main factor determining the tax residency in Poland is the length of stay – 183 days in the tax year or having a centre of personal or economic interests (centre of vital interests) in Poland. This means that a person who meets these conditions should account for the Polish tax authorities of all his income, not only Polish income but also worldwide income taking into account agreements on avoidance of double taxation. Surely it is better to submit an annual statement correction showing the revenues not previously reported and to pay the Polish tax before the tax office comes to us with the formal control. Under certain conditions, one can avoid the severe penalties resulting from the Polish Criminal Code and pay less than the statutory interest for late payment.