Veteran comedic actor Pat Finn — who starred in sitcoms like “The Middle” and “The George Wendt Show” — died from bladder cancer … according to his death certificate.

The document, obtained by TMZ, says Pat had a cancerous tumor in his bladder for years … and there were no other significant conditions contributing to his death.

As we reported … Pat died from cancer Dec. 22 at his Los Angeles home, surrounded by family.

It was unclear when Pat died what type of cancer he was fighting, but there had been reports he was diagnosed several years ago with bladder cancer … and that turned out to be the case here.

Pat came up in Hollywood around the same time as his good friend Chris Farley. They both played rugby at Marquette University in 1987 and were roommates in Chicago when they both joined the Second City comedy troupe.

In the early ’90s, Pat scored a guest role as Joe Mayo on “Seinfeld” … and he went on to play Dan Coleman on “The George Wendt Show,” and Phil Jr. on “Murphy Brown.”

Pat is probably best known for his role on “The Middle,” where he played Bill Norwood from 2011 to 2018.

The death certificate notes Pat worked as an actor for 35 years … and it says his remains were cremated.

He’s survived by his wife Donna and their 3 children.