Rapper Biz Markie -- most famous for his iconic hit "Just a Friend" -- has died after a series of complications from diabetes that he's been fighting for more than a year ... TMZ has confirmed.

A family source tells us Biz passed away in a Baltimore hospital at 6:25 PM Friday night. We're told his wife, Tara Hall, held his hand as he took his last breath ... and the nursing staff was there to support his family, telling them how strong he was through his fight.

tmz.com