12th December 2018, 06:09 | Leeds
The Gdansk-born Oledzki, 20, cemented his place in the Rhinos squad in 2018 with 22 appearances and went on the end-of-season Knights tour to Papua New Guinea.
Leeds director of rugby Kevin Sinfield said: “I am delighted that Mikolaj has agreed a new long-term contract with the club.
“He has worked incredibly hard over the last few years to develop his game but he would be the first to admit that there is still plenty he can work on over the coming years.
“He is one of the most enthusiastic members of our squad and he earned his place in the England Knights squad through his performances last year.
“For a prop, he is still young but, if he continues to develop, he will have a bright future in the game.”
Oledzki, who has been handed the number 19 shirt in new coach Dave Furner’s 2019 squad, said: “It is great to have my new contract all sorted.
“I have signed the new deal because I believe Leeds is one of the greatest clubs in the world and I want to play here.”