The declaration, made by Gov. Rabiu Kwankwaso, sets the north of Nigeria more firmly than ever on a collision course with the government of President Olusegun Obasanjo who has appealed repeatedly for the Islamic code not to be enforced.
From early Wednesday, hundreds of thousands of Muslims, mainly young men, packed into the Eid Ground in the centre of Kano to witness the declaration of the strict Islamic code, known as Sharia.
Two people were crushed to death by the crowd, estimated by officials at up to one million, and more than 50 fainted and were hospitalised in the heat, hospital officials said.
Kwankwaso, who had to cut short his address to the crowd because of fears over crowd safety, told government and religious dignitaries it was a historic day in the city, founded as a slave and gold trading centre 1,000 years ago on the edge of the Sahara desert.
"This is a momentous day in the history of Kano State. It is the day that Sharia is launched," Kwankwaso told officials here.
The governor said he had been advised by the Kano State chief imam, Sheikh Isa Waziri, that the best date to start enforcing Sharia would be the first day of the Islamic holy month of Ramadan, due this year in early December.
"We have agreed," he said.
Before then, the Kano version of the code setting out legal provisions and punishments will be drawn up, Islamic courts will be established and an Islamic judiciary will be trained, he said.
Waziri said it was a day to be celebrated by every Muslim.
"Sharia is the backbone, the compass, of Muslims all over the world, showing them their direction," he said.
Fears have been expressed that some sections of the Muslim youth in Kano would use the occasion to attack minority Christians living in a ghetto known as Sabon Gari.
Kwankwaso said that Islam was a religion of peace and tolerance and that any attacks on those of other religions were un-Islamic.
"Islam urges people to follow in the footsteps of the prophet, and show patience, honesty and trustworthiness and preserve the rights of women, children and neighbours," he said.
However, the governor said the code would be enforced in hotels, federal army and police barracks, and areas of the city that are dominated by Christians.
"In the whole of Kano State, there will be no area where Sharia is not implemented. There will be no exceptions," he said.
Outside the crowd celebrated with great cries of "Allahu akhbar" (God is Greater) and Islamic lawyer Abubakar Mika'il Hassan explained that Muslims believed that the introduction of Sharia would cure the many problems besetting this country.
"This has a very long history in Nigeria," Hassan told AFP.
"We Muslims have been yearning to see the Sharia code be implemented for many years. It is our right. We are grateful for the God almighty that Sharia will be implemented today," he said.
The declaration of plans to introduce Islamic law in Kano makes the state the fourth since October to declare Sharia, though one of those states, Niger, has partly rescinded.
Attending the ceremony Wednesday were several northern state governors including the governor of Yobe state, who announced he had sent a bill on Sharia to his State House of Assembly, and the governor of Jigawa, who said Sharia would be declared there on August 2.
Katsina and Kaduna states are also under pressure to declare the code.