No terror group immediately claimed responsibility for it.
The deceased included six children and two women besides 18 members of a family, who were there to attend a wedding ceremony, hospital authorities said.
Pakistan President Mamnoon Hussain and Prime Minister Nawaz Sharif strongly condemned the blast.
The deadly explosion, which took place at about 10.50 a.m. at Qissa Khawani Bazar, one of the busiest markets in Peshawar, was planted inside a car parked about 20 metres from a police station in the market.
As much as 200 - 225 kg of explosives were used in the blast, said Additional Inspector General Bomb Dispotal Squad Shafqat Malik, adding that time device was used for the blast.
Meanwhile, a fire which broke out after the blast engulfed a number of shops. The blaze also destroyed three plazas. The blast also destroyed several vehicles -- rickshaws and motorbikes.
President Hussain and Prime Minister Sharif said the determination of the nation to fight terrorism remains strong.
While condemning the blast‚ President Hussain in his message termed the bomb blast as a barbaric act. He expressed his sorrow and grief over the loss of precious lives due the blast.
Condemning the blast, Nawaz Sharif, who is in the US for the UN general assembly's General Debate, said that those involved in the killings of innocent people were devoid of humanity and all religions.
The brutal acts of terrorism could not deter the government's resolve to ensure peace in the country, he added.
Meanwhile, Governor and Chief Minister of Khyber Pakhtunkhwa province also condemned the incident and expressed sympathies with the bereaved families.
Sunday's blast was the third serious terrorist attack in the city over the past week. A twin suicide bomb attack Sep 22 on a Christian church in Peshawar, claimed more than 80 lives, triggering a nationwide protest.
A bus carrying local government employees was blown up by a bomb planted inside it Friday, leaving at least 19 people dead.