Carey, 33, was met on Tuesday night with loud cheers and warm applause when she appeared on the stage in a two-piece, silver outfit at an exhibition and leisure centre on the Mediterranean seafront in downtown Beirut.
"Thank you for being so welcoming," Carey said to the crowd of about 5000, who included the wives of the president and prime minister of Lebanon.
Impressed by the Beirut fans, Carey was heard telling her bodyguards, "Wonderful, wonderful."
Carey enchanted the fans with hits including Butterfly, Hero and Dreamlover. Her concert, the first in the Middle East, was organised by the Beiteddine Festival Committee.
"It was really good. It was really good," 15-year-old Tina Choueiri said of the 90-minute concert. "Her voice was amazing."
Carey, who has sold more than 150 million records and won two Grammy Awards, arrived in Beirut on Monday as part of a world tour designed to promote her latest album, Charm Bracelet. She will perform in Dubai on Thursday.