Beckett: The thing about murderers. Mario, is they tend to not have solid alibis.
Castle: Generally because they are murdering somebody.

Castle: What's the strangest pet you've ever had?
Beckett: You.

Auditions are like men, there is always another one around the corner.

Martha

Haven't these guys gotten the memo about the correlation between sun tanning and skin cancer?

Firemen? Really? Isn't that a little cliche?

Ladies, I am not a stripper, though I can understand how you'd make that mistake.

Have you ever heard of a brilliant doctor named Doogie Howser?

I had a dream I was floating on a lily pad with the Swedish swim team giving great reviews to Nikki Heat.

Cable guy and creepy - thats a job requirement.

Captain Montgomery: Feds say he is a white male, 25 to 45 years old.
Castle: Could be me.
Captain Montgomery: With a dysfunctional relationship with his mother.
Castle: Still me.
Captain Montgomery: He has a menial unimportant job.
Beckett: Definitely you.
Castle: Just for that my next book is based on Esposito.

It's like a mystery novel, you don't just go to the last page do you?

Nothing says I'm an ass like a bunch of helium filled rubber.

Castle Season 3 Quotes

He really is ruggedly handsome.

Ryan (looking at cutout of Castle)

Ryan: (drops egg off desk)
Beckett: Are you guys reenacting the "Humpty Dumpty crime scene?"