Roughly 100 neglected cats were rescued from a urine-drenched Long Island house of filth whose owner may have been selling the felines online for thousands of bucks, authorities said Wednesday.

Law enforcement found more than eight dozen matted-up Maine Coon cats covered in dirt and fleas Tuesday morning after an anonymous tip pointed them to the West Islip home, the Suffolk County SPCA said.

“The conditions inside the home were deplorable,” said SPCA chief Roy Gross. “From the outside, you’d never know what was going on behind those closed doors.”

He said the disgusting smell emanating from the house was “overwhelming” with cat urine and feces, as well as piles of trash, covering the floors.

The cats were also underweight and suffering from open sores, Gross said.

The rescue effort lasted nearly 24 hours, starting early Tuesday and not ending until about 3 a.m. the following day.

Grace Etzelsberger, 66, was charged with misdemeanor animal neglect on Tuesday, authorities said.

Gross said investigators are also probing if Etzelsberger, a cat breeder for more than 20 years, was properly licensed. Her website, Graro Maine Coons Cattery, and her social media accounts have been nuked since the raid.

But she was actively selling cats just one day before authorities descended on her home, her website showed before it was shut down.

Her house has also since been condemned and deemed not livable by the town of Islip fire marshal, the SPCA said.

Authorities are expected to still check out the house moving forward to ensure every cat was pulled to safety in case any felines have been hiding in different nooks and crannies.

The recovered cats have been seen by veterinarians and put up for adoption with the help of rescue groups across Long Island, Gross said.  

Neighbors said Wednesday they were shocked by the gross find.

“That can’t be healthy for anyone,” Zach Siano quipped to The Post. “What if a cat started attacking me? There’s hundreds of them!”