In an interview with The Associated Press, 50 complained that Winfrey rarely invites rappers on her talk show: "I think she caters to older white women."
"Oprah's audience is my audience's parents," the 29-year-old rapper said. "So, I could care less about Oprah or her show."
He's not alone in his resentment toward the talk show host cum media mogul.
Rapper-actor Ludacris, aka Chris Bridges, said in the May issue of GQ magazine that Winfrey was "unfair" during a show he appeared on last October with co-stars from best-picture Oscar winner "Crash."
"She edited out a lot of my comments while keeping her own in," he said. "Of course, it's her show, but we were doing a show on racial discrimination, and she gave me a hard time as a rapper, when I came on there as an actor."
Winfrey's representative at her production company, Harpo, told the AP that Winfrey was unavailable for comment.
But, as 50 Cent said, Winfrey's purported disapproval might enhance a rap star's street cred.
"I'm actually better off having friction with her," he said.
The crack-dealer-turned-rapper has sold millions of records gleefully flaunting his gangsta image, explicit lyrics and bulletproof vest (he was famously shot nine times). He has his own record label, G-Unit, the G-Unit clothing line, his own sneaker line with Reebok and a videogame, "Bulletproof."
And he wears his rough-and-tumble reputation proudly: "I don't mind it. I've actually accepted it."
The rapper, who's signed to close pal Eminem's Shady/Aftermath label under Interscope Records, said he recently attended Proof's wake with Eminem. Proof, a friend of Eminem's, was shot and killed earlier this month during a dispute in a Detroit nightclub.
"He's coming along," he said of Eminem. "He's gonna be all right. I mean, it was definitely a big loss for him. Proof was actually his best friend in the world from forever."
On the heels of Proof's death, a study released last week by the Pacific Institute for Research and Evaluation — a nonprofit public health research group — suggested that young people who listen to rap music are more prone to alcohol and drug use and aggressive behavior.
But 50's not buying it.
He points a finger at parents, who he thinks should explain to their children that his music is a form of entertainment, not a license to break the law.
"I think that the violence that happened to Proof and the violence that's happening across America right now has nothing to do with hip-hop," he said. "It has something to do with the people — the state of them — and the music doesn't alter that."