The bluesy rant--about Cher's time in a Catholic orphanage as a kid--labels the order "daughters of hell," "masters of pain," "mothers of shame," "twisters of truth," and "daughters of war."
The twice-divorced diva also rails:
"Sisters of Mercy, they always weave the web of lies and wrap you in their wicked spell.
"They use God like he's a weapon but only for a chosen few, then hide behind pious faces like the guilty always do.
"These chicks administer your penance, while the devil guards their door."
The Catholic League slammed the bitter lyrics, saying Cher--who penned the song herself--should be ashamed.
"Cher, much like the rest of Hollywood, is trying to sell her CD on the backs of Catholics. It's reprehensible," spokesman Patrick Scully said.
"It's another instance of Hollywood and the entertainment industry using Catholic imagery in a negative way to try and sell their wares.
"Obviously, she needs an angle to sell the album. Let's face it: It's not 'American Pie.'"
Cher, 54, says her angry words come from the fact her mom was forced to put her into a Catholic orphanage while she worked at an all-night diner.
"When she went to get me back, the mother superior told her she should put me up for adoption. It took my mother six months to get them to release me back to her," Cher explained.
"She felt desperate and helpless against the establishment. This is not a condemnation of the Catholic Church.... I have known many wonderful and loving nuns in my life."
Sister Camille D'Arienzo, president of the Brooklyn regional chapter of the Sisters of Mercy, said of the song:
"If her charges are true, then there is no one of us who would not express sorrow.
"If they are not true, such harsh criticism, while being unfair, also carries a warning to all...who are responsible for the care of all people young or elderly.
"She's an artist, too, so there also lingers the question of how much imagination preys into an artist's memory."
The song is on Cher's new record, "Non-Commercial," which will be sold through her website beginning next week.
The CD comes with a not-suitable-for-kids warning label and is a far cry from her last album, which features the disco smash "Believe."
The Sisters of Mercy serve the poor and sick, with a special focus on women and kids.