Career
He was re-elected for his seventh term in October, 2007, winning 13271 votes. He is representing Chełm (7th district). Known as one of his party leaders, he served as a Sejm Vice-Marshal from 1997 until 2001 (alongside Marek Borowski of Democratic Left Alliance, January Król of Freedom Union and Stanisław Zając of Solidarity Electoral Action.
From 2001 to 2005 he was chairman of the Sejm Constitutional Commission.
Stefaniuk is an economist.