The 56-year-old star told Billboard that the book holds little appeal for her.
"Yes, I have (read it). It's pulp fiction. It's not very sexy, maybe for someone who has never had sex before," she said.
"I kept waiting for something exciting and crazy to happen in that red room thing, and I was like, 'Hmm, a lot of spanking,'" Madonna said.
A movie adaptation, starring Dakota Johnson and Jamie Dornan hit the screens this week.