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The 95-year-old cancelled two appearances to major conventions last year due to illness but the emergency services reported he is currently in a stable condition.
A spokesperson for Mr Lee said: “He is doing well and feeling good, he is staying there for a few days for some check ups as a safety precaution."
The comic book hall of fame inductee has co-created fictional characters including Spider-Man, the Hulk, Doctor Strange, the Fantastic Four, Daredevil, Black Panther and the X-Men, among others.
His admittance comes after the famed creator became ill at his home on Wednesday.
Mr Lee was last seen at the premiere of Black Panther on Monday night.
His wife, Joan, died last July after suffering from a stroke - she was 93 years old.
Lee is widely known for his cameo appearances in superhero blockbusters - he has been spotted on-screen in over 30 movies.
The legend, also known as Stanley Martin Lieber, was born on December 28, 1922, before going on to create a slew of incredibly popular characters that would go on to change comics and film forever.
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