The following list is of the largest deserts of the world, split into three categories

SUBTROPICAL

Sahara, North Africa 3,500,000 sq. miles
Arabian, Middle East 1,000,000 sq. miles
Great Victoria, Australia 250,000 sq. miles
Rub'al Khali, Middle East 250,000 sq. miles
Kalahari, Southern Africa 225,000 sq. miles
Syrian, Middle East 200,000 sq. miles
Chihuahuan, Mexico 175,000 sq. miles
Thar, India/Pakistan175,000 sq. miles
Great Sandy, Australia 150,000 sq. miles
Gibson, Australia 120,000 sq. miles
Sonoran, S.W. USA 120,000 sq. miles
Mohave, S,W, USA 54,000 sq. miles

COOL COASTAL

Atacama, Chile SA 54,000 sq. miles
Namib, S.W. Africa 13,000 sq. miles

COLD WINTER

Gobi, China 500,000 sq. miles
Patagonian, Argentina 260,000 sq. miles
Great Basin, S.W. USA 190,000 sq. miles
Kara-Kum, West Asia 135,000 sq. miles
Colorado, Western USA 130,000 sq. miles 
     (also called the Painted Desert}
Taklamakan, China 105,000 sq. miles
Iranian, Iran 100,000 sq. miles