One million Syrians are going hungry and without proper shelter, in freezing conditions, according the United Nations.
The UN's World Food Program (WFP) says fighting and fuel shortages are stopping aid from getting to people.
Since fighting broke out nearly two years ago, many have been forced to leave their homes.
They live in refugee camps in Syria and nearby countries including Lebanon, Jordan and Turkey.
Officials say nearly 100,000 people have fled the violence in Syria in the past month alone. That puts the total number of refugees at more than half a million.
The WFP says there has been a big rise in the number of attacks on aid trucks, which have also been hit by fuel shortages.
And a lack of food isn't the only worry. Temperatures are freezing and it's snowing in many places.
The UN estimates that more than 60,000 people have been killed in the conflict, which began in March 2011.