The 26th and 27th members of the European club will be allowed to join up after the EU's executive arm proclaimed they have made sufficient reforms but added that monitoring, with the threat of sanctions, will continue in areas of special concern.
According to the draft report circulating in Brussels, but still subject to last-minute alterations, the commission finds that Bulgaria and Romania have reached "a high degree of alignment" in their preparations for membership.
But for the first time ever, the commission will create a permanent monitoring mechanism to ensure new members meet their obligations, according to a European diplomatic source.
Of particular concern are the areas of crime and justice, use of EU funds, corruption and food safety.
Swine fever in both countries means a pork import ban will be maintained.
"They'll be welcomed in, but the welcome mat has some terms and conditions attached," a European diplomat said.
Britain has already warned that it is likely to put a cap on immigrants from Bulgaria and Romania, after half a million east Europeans flooded the country since 2004.
But Romania's Prime Minister Calin Tariceanu says entry into the EU will not spark a wave of mass emigration.
He appealed to current EU member states to keep their borders open once Romania and Bulgaria join next year: "Free movement of workers should be respected by all member states."
Bulgaria is determined to continue its reforms after joining the coveted group, Bulgarian European Affairs Minister Meglena Kuneva said.
Bulgaria and Romania will be among the poorest members of the EU, making up six percent of the bloc's population but less than one percent of its gross domestic product (GDP).
Last in
But Romania and Bulgaria may be the last countries to join the EU for a while, with EC president Jose Manuel Barroso saying further enlargement should be frozen until EU member states decide on reforms to streamline decision-making.
"It would be inadvisable to have any more member states in the union, apart from Romania and Bulgaria, before sorting out the institutional question," Mr Barroso said.
Croatia, which hopes to join the EU in 2009, would likely be the first to feel the affects of any enlargement freeze.