Used to watch this movie every time it came on TV when I was a kid.

Bud Abbott was the straight man in the duo. While he occasionally had some funny bits his main function in the duo was to set up the joke.

When I was young and I knew this movie was coming up I couldn't wait to get home from church

No, the original Frankenstein monster was played by Boris Karloff. Glenn Strange was playing the Frankenstein monster in the most recent Frankenstein movies at the time ("House of Frankenstein" and "House of Dracula"). Lon Chaney Jr. who played Larry Talbot/The Wolf Man was the original Larry Talbot/The Wolf Man, and of course Bela Lugosi was the original Count Dracula. This movie was a perfect mix of the Universal  monsters with the team of Abbott and Costello, blending suspense and horror with comedy! An excellent closure and homage to both franchises. Note: You definitely should watch the original Wolf Man (1941). I know you will enjoy it!

This movie was the highest grossing Comedy of 1948.

SO glad to know you respect the Universal Pictures classic monsters! Boris Karloff played the original Frankenstein monster but due to the heavy costume and shoes etc. developed a lot of physical issues and had backaches and health problems the test of his life. Bela Lugosi was offered the part originally but the heavy makeup and lack of dialogue made him feel it was beneath him so he turned it down.  It made him come across as "difficult to work with" and made it more difficult to get roles in the future.  Karloff was considered  a "nice guy" and became very successful as a "horror" actor while Lugosi struggled and even settled for playing "the Monster" in "Frankenstein Meets the Wolfman"
Starting to get off topic here so to answer your question about Frankenstein's monster that is sometime Western movie villain Glenn Strange as the creature

ABBOTT & COSTELLO MEET THE INVISIBLE MAN is another excellent mad scientist movie they did!

HOLD THAT GHOST is a great Abbott & Costello movie as well

Great reaction! Be sure to watch The Wolf Man (1941) now. It's tremendously atmospheric and well done!

During the scene where the Frankenstein monster threw the female doctor through the window, the actor Glenn Strange stepped on a cable and broke his ankle. To avoid delays, Lon Chaney Jr (the Wolf Man) volunteered to don the Frankenstein monster make-up (he played the character in 1942's "Ghost Of Frankenstein") for the remainder of the scene and when he turns back toward Abbott and Costello you can tell by his facial expressions that it is Chaney.

A few years after this, they made Abbott and Costello Meet the Invisible Man .

My second favorite horror comedy after “Young Frankenstein.” Lou Costello was one of the funniest comics ever.

thanx so much for watching this and sharing i grew up with this movie WPIX sundays.

Every Halloween I watch this and The Ghost and Mr. Chicken. Two of the best horror comedies ever mad.

There's a bunch of outtakes from the scene where Costello sits in the monster's lap.  The guy playing the monster keeps cracking up laughing.

This movie introduced me to Dracula, Frankenstein and Wolfman. Scared me shitless when I was a kid.

YES!
I love the universal monsters
And this film is great.

Bud Abbott was the greatest straight man in the history of comedy!

This is one of the great ones i got this on dvd.

The scene with the candle moving is hilarious 😅