The plane came down in a densely-populated area
President Obasanjo reaffirmed a pledge to conduct a full inquiry into the crash and visited Emir Ado Bayero, Kano's traditional ruler, to express his condolences.
The Nigerian Red Cross said at least 148 bodies had been recovered and 49 people were seriously injured, while hundreds of others had been made homeless.
Not publicised
President Obasanjo pledged $86,000 of federal government funds to compensate families of the victims.
"The nation is in grief and in a state of mourning," he said in remarks released to reporters by the Emir's palace.
The BBC's Ado Saleh Kankia in Kano says many locals were not aware of the president's presence.
The visit was not publicised in advance, and took place under heavy security.
Our correspondent says the government was probably keen to avoid a repetition of the trouble sparked by Vice-President Atiku Abubakar's visit on Saturday.
Police used teargas to disperse opposition supporters who disrupted a speech by Mr Abubakar and pelted his convoy with stones.
Survivors
Spontaneous street protests broke out over the weekend at the crash site - where the plane had ploughed through tin-roofed houses, a mosque and a Koranic school.
Four people on board the plane are reported to have survived - one female crew member, and three passengers, one of whom was a Lebanese national, officials from the privately-owned EAS airline said.
One of the survivors, Najib Ibrahim, told the BBC's Network Africa, that he prayed as the plane came down.
"After a few seconds I unfastened my seatbelt and jumped outside," he said. "People don't believe I'm alive."
One of those who died was Sports Minister Ishaya Mark Aku.
He had been on his way to Lagos to see a World Cup warm-up match for Nigeria's footballers.
Flags at half mast
After the crash President Obasanjo called for an "immediate and detailed investigation" into the crash, involving foreign experts if required.
The president ordered flags to fly at half mast "as a mark of honour to the deceased".
Rescue worker Shehu Tofa told the French news agency AFP that the plane's black box flight recorder had been recovered.
This is the worst aviation disaster in Nigeria since 1966 when a domestic flight crashed near Lagos with a loss of 142 lives.
Nigeria deregulated its airline industry in the mid-1980s and about a dozen private companies, including EAS, sprang up to compete with state carrier Nigeria Airways.
Correspondents say there are concerns about the use of older aircraft by the private domestic carriers, and some foreign embassies have forbidden their staff from flying on certain airlines because of safety concerns.
In April, the Nigerian Government announced a ban on the use of aircraft more than 22 years old, a move that triggered strong protests from private local airline operators.