Starting from 2018 PIT exemptions for gambling winnings were changed. In particular, all types of gambling (therefore, online casino as well) organized and run by an eligible entity under the gambling legislation in force in a Member State of the European Union or in another country belonging to the European Economic Area are PIT exempt only if the one-time value of winnings does not exceed PLN 2280 (only winnings in a poker tournament are subject to exemption without limitation). Moreover, the new provisions define the one-off value of winnings, which in the case of winnings in a casino or slot machine game leads to the conclusion that the taxable amount should be equal to lost amounts (according to the definition the taxable basis is equal to the amount earned, being the difference between the sum of the paid bids and the sum of the winnings paid during a one-off stay in a casino or a one-off slot machine game). 

Now the Ministry of Finance wants to withdraw from some changes, removing also the unfortunate definition of taxable amount. According to the draft of January 8, 2018 full PIT exemption will be restored starting from March 2018 (however effective from January 2018) for slot machine games, card games, dice games, cylindrical games, bingo games, cash bingo games. The link to the project may be found here.

http://blogs.dlapiper.com/all-in/2018/01/18/further-changes-to-pit-exemption-for-gaming-players-in-poland/#more-3517