Burj Dubai -- which means "Dubai tower" in Arabic -- has taken 12,000 labourers six years to complete.
Started at the height of the economic boom, the opening of the tower has been delayed twice since construction began in 2004.
Its completion marks another milestone for the emirate which has a penchant for breaking records but which has recently found itself in the depths of a financial crisis.
The project has been scrutinised by human rights groups, who have objected to its treatment of labourers, as well as by environmentalists who said the tower would act as a power vacuum, increasing the city's already massive carbon footprint.
But despite the criticism, many say the edifice, believed to have cost $1.5 billion to build, is an architectural marvel.