In a communique released at the end of the summit, the three leaders promised to co-operate on several issues.
"We build our collaboration on the understanding that our deepening ties are a source of strength and that challenges and opportunities in one North American country can and do affect us all," the statement said.
The three countries said that a "co-ordinated response to the outbreak of the H1N1 flu virus" had shown that international co-operation was possible.
"We will work together to learn from recent experiences and prepare North America for the upcoming influenza season, including building up our public health capacities and facilitating efficient information-sharing among our countries," the communique said.
Obama and Harper also agreed to maintain support to the Mexican government in its fight against drugs traffickers.
"Canada and the United States recognise the commitment and the sacrifices of the Mexican people and government as they confront the cartels threatening society, and we pledge to them our continued support," the communique said.
The pledge comes after the US congress agreed to give at $1.4bn in aid to Mexico as part of the three-year Merida initiative, a US plan aimed at tackling drugs cartels and money laundering.
But Obama urged Calderon to ensure that Mexico's security forces respect human rights during their pursuit of the gangs, following allegations of abuses committed by soldiers during the crackdown.
Just hours before the talks, a commando shot dead a lawyer known for her work in defending suspected drug smugglers in the north of the country.
Calderon said on Monday that the Mexican government was committed to ensuring that human rights are protected while in pursuit of drugs gangs.
"We know that we are destroying their criminal organisation. We're hitting them hard We're hitting at the heart of the organisations," he said.
On the economic recession, the leaders said that a strong partnership was needed to speed up an eventual recovery.
"Promoting recovery from the current global economic crisis is a priority for each of us. By working together, we will accelerate recovery and job creation, and build a strong base for long-term prosperity," the statment said.
|The leaders want a lasting deal between Zelaya and Honduras' interim government [EPA]
The leaders said they agreed that mutually beneficial trading relationship was key to tackling the economic crisis, but Harper said he was concerned about "Buy American" clauses in the US' $787bn domestic fiscal stimulus plan.
Canada is concerned that those provisions could hurt exports of its goods to markets in the US.
Obama said the "Buy American" measuress do not amount to protectionism and that they have "in no way endangered the billions of dollars in trade" between the US and Canada.
The communique also said that North American nations had pledged to work towards "a successful outcome" at UN climate conference in Denmark in December.
"We, the leaders of North American reaffirm the urgency and necessity of taking aggressive action on climate change," the joint statement said.
The leaders also said that they are committed to a peaceful resolution between the ousted president of Honduras and country's interim government.
Obama brushed off a claim that the US had not done enough to help Manuel Zelaya, the deposed Honduran leader, return to power since he was forced from the presidency on June 28.
"The same critics who say that the United States has not intervened enough in Honduras are the same people who say that we are always intervening and the Yankees need to get out of Latin America," Obama said.
"You can't have it both ways."