The 30-year-old Irishman was charged with criminal mischief and strong-armed robbery after Miami police said he allegedly slapped the phone out of the fan's hand and then stomped on it.
Miami Beach police said they were called to the scene outside the LIV Nightclub at 5:00 am (0900 GMT), The Miami Herald reported.
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The police started their investigation and McGregor was arrested later that day at a nearby home and then booked into the Miami-Dade jail.
According the arrest report, the fan tried to take a photo of McGregor using his mobile phone, valued at $1,000. After the fighter allegedly slapped it away and then stomped on it, he took the phone without giving it back.
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The robbery was caught on surveillance cameras set up around the club and the nearby Fontainebleau Hotel.
McGregor is a mixed martial arts star who is best known for losing to boxing icon Floyd Mayweather in a 2017 boxing match.
Bail was set at $12,500.
McGregor was arrested last year in New York after police said he attacked a charter bus carrying several rival martial arts fighters, throwing a dolly through the window.
He pled guilty to disorderly conduct and was sentenced to community service and an anger management course.
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