He was speaking after a mini summit between the two sides in Brussels on Monday.
After the informal talks, Poroshenko said, "We have discussed a series of important issues and coordinated our actions on the visa-free regime. We expect formal procedures to be completed by summer holidays in the Ukraine Parliament."
According to Poroshenko, there are no obstacles for the continuation of work aimed at the introduction of the visa-free regime.
"I see no difficulties. There are objective difficulties caused by Brexit, but they will lead only to postponement for days, perhaps weeks," he noted.
Also taking part in the one day talks were the President of the European Council Donald Tusk, President of the European Commission Jean-Claude Juncker and President of the European Parliament Martin Schulz.
The two sides mostly discussed the abolition of the visa regime with the Schengen countries for Ukrainian citizens.
He said the parties also reached an agreement on the provision of macro-financial aid to Ukraine and was hopeful that the given issue would be resolved shortly.
"After the IMF makes a decision to allocate another tranche to Ukraine, the EU will provide macro-financial aid to Ukraine together with loan guarantees from the United States," Poroshenko said.
According to the Ukrainian President, the EU leadership has praised the efforts of the Ukrainian authorities aimed at the implementation of the constitutional reform, anti-corruption legislation, deregulation reform and election of new Prosecutor General.
"The meeting was held in a friendly atmosphere and we are grateful for a consistent and firm position of our European partners in such a difficult time for both Ukraine and the EU," he said.
Poroshenko also had a separate meeting with Schulz.
The parties shared views regarding the results of the UK referendum on EU membership and its influence on Ukraine-EU relations.
Poroshenko expressed hope that current internal difficulties would not focus the EU's attention solely on its own problems.
He was hopeful they would become a "stimulus" for the search for new successful European integration projects.
"And Ukraine can become such a project," he said.
Schulz said that the internal procedures related to the UK leaving the EU would not affect readiness of the European Parliament to introduce the visa-free regime for Ukrainian citizens.