Zardari's visit to Europe comes amid a massive offensive by government forces against the Pakistasni Taliban in the country's northwest which has led to the displacement of about two million people.
Jose Manuel Barroso, president of the European Commission, the EU's executive body, said at a joint news conference with Zardari that the EU would be offering Pakistan an additional $100m in humanitarian aid to help those hit by the crisis.
'Trade, not aid'
The summit comes as Pakistan says it is about to launch a major offensive against the Taliban along the Afghan border.
Nato and the EU are keen for Islamabad to succeed against the Taliban in Pakistan, as the Taliban have been using the country's tribal areas as a base in their fight against Nato forces in Afghanistan.
After earlier holding talks with Nato ambassadors, Zardari said: "With the help of the world we will win this, and half the war is the hearts and minds of the people.
"What I need is trade, not aid. I'm looking for MOUs [memorandums of understanding] and not IOUs and I intend to get them."
According to a draft text, the EU will "explore" how Pakistan could benefit from its preferential tariff regime, which affords customs privileges in return for respecting principles in the areas of workers' rights and the environment.
Discussing the extra money to be provided to Pakistan, Benita Ferrero-Waldner, the EU external relations commissioner, said: "In exchange, we want Pakistan to take the fight against terrorism very seriously and that they do a lot on their home front.
"That means all the questions of good governance, on education ... then we will be excellent partners."
Fears are growing of a broad humanitarian crisis in Pakistan's Swat valley and surrounding areas as the fighting there spreads.
Oxfam has called it "the world's biggest and fastest growing human displacement in over a decade" and said funds to help the displaced remained inadequate.
"The total figure of internally displaced persons is likely to rise as military operations extend into other areas," it said in a statement Tuesday.
The British-based aid organisation targeted the EU for its "feeble response to the humanitarian crisis."
A US senate committee voted on Tuesday in favour of trebling non-military aid to Pakistan to $7.5bn over five years.