The attacker, wearing an explosives belt, blew himself up at 10:20 pm (1930 GMT) at the cafe in the Wahad Hozeran district, said police and Dr Sabah Mohammed Amin, the city’s health chief.
The blast came after attacks mainly targeting security forces killed nine people, including a police brigadier general, earlier on Friday a day after 56 people died in bombings and shootings.
Iraq is experiencing a surge in violence across the country where more than 2,500 people have been killed this year, including more than 275 this month alone.
Authorities in the northern Iraqi city of Kirkuk have ordered all cafes to be shut down a day after a suicide attack killed 39 people when a bomber detonated his explosives in a crowded coffee shop.
Police chief Maj. Gen. Jamal Tahir said on Saturday that his troops cannot secure dozens of teahouses and coffee shops scattered across the city. Kirkuk is 290 kilometers (180 miles) north of Baghdad.
Tahir says he has not yet decided when the coffee shops will be able to open again.
Iraq is being rocked by its deadliest and most sustained wave of bloodshed in half a decade.