The blast occurred at a bus stop in the provincial capital Quetta and the area caught fire soon after the explosion.
“We can now confirm that 15 people have died in the explosion today. At least 32 others are wounded,” Balochistan home minister Sarfraz Bugti told AFP, adding that a rescue operation was still underway.
A spokesman for the Balochistan government, Anwar ul Haq Kakar also confirmed the toll.
Bugti workers were busy extinguishing the blaze. He said the holidays of all doctors in the city were suspended.
The nature of the blast could not immediately be determined but an investigation was underway, Bugti said.
There was no immediate claim of responsibility but Taliban and Islamic State militants have attacked Quetta city in the past.
Balochistan has oil and gas resources but is afflicted by Islamist militancy, sectarian violence between Sunni and Shiite Muslims and a separatist insurgency.
Download our app and read this and other great stories on the move. Available for Android and iOS.