The 24-year-old Netherlands international moves from the Eredivisie to the Premier League and becomes Mark Hughes' first major transfer of the summer after replacing Tony Pulis
The 24-year-old joins the Potters to become new manager Mark Hughes' first major transfer of the summer, signing a four-year deal.
Pieters spent five years at PSV, making 140 appearances in all competitions, but lost his place to Jetro Willems after an injury plagued 2012-13 season.
He has welcomed the move to the Britannia Stadium, revealing on Twitter: “Happy to sign at Stoke City for four years. #NewStart, big thanks to PSV and the supporters for the last five years.”
Stoke boss Hughes told the club's official website: “I am delighted to have secured Erik's signature. The main focus this summer in attempting to strengthen the squad is ensuring it is balanced in key positions.
“While Erik is predominantly a left back, he has also played for his country as a central defender, so he gives us other options.
“We need good quality in our starting eleven and good quality back-up for all areas, which Erik will certainly give us defensively.”