The EU will set up a single hotline for parents to report missing children.
The missing children's hotline should be available by summer
Calls to the new phone number - 116000 - will be free of charge and it is expected to be launched by summer.
Several of the EU's 27 member states already have their own missing children hotlines, but this is the first attempt to set up a common phone number.
At least 120,000 children are known to live outside their home country without supervision in the EU, according to a European children's organisation.
The European Network of Ombudspersons for Children (ENOC) says this figure only includes children known about by the authorities.
The hotline may be run by private organisations in each country.
The EU says it will also consider launching other common social services hotlines starting with the first three digits 116.
"I am delighted that today the first major step towards a single EU hotline number for missing children has been taken," EU Telecom Commissioner Viviane Reding said.
"I urge member states to act now to make this a reality, so that Europe's parents will soon know that they are able to call this number and get immediate help."
The EU already has a common emergency number - 112 - which was set up in 1991.
But earlier this month some MEPs said that more than two-thirds of Europeans were unaware of its existence.