Polledri, born in England, qualified for Italy through his grandparents and played for them at Under-20 level before making his senior debut in 2018. He represented the Azzurri 20 times.
His career was hit by a devastating injury with Italy in 2020 when he ruptured all three cruciate ligaments in his knee, tore his hamstring off the bone and tore his calf which resulted in damage to the nerves and paralysis of his foot.
Polledri played for Gloucester at the time but joined Zebre Parma in 2023 and made his last appearance for Italy in last year's Six Nations, coming off the bench against England.
"My foot however hasn't returned back to 100% and ultimately it has affected my ability to return to the high level of rugby I played, and it has also affected life generally," Polledri said on Instagram.
"I have reluctantly accepted that my body and professionals are telling me retire from the sport that I love."
Polledri participated in four Six Nations championships and also played at the Rugby World Cup in 2019.
"We lose an extraordinary player, he remains a fantastic person who can be a valuable asset and a great ambassador for our rugby. I thank him for what he has given to the jersey of our national team," Italian Rugby Federation President Marzio Innocenti said.
