Chancellor Alistair Darling told parliament that an extra £100 each year will be paid into trust accounts of disabled children, with severely disabled children receiving £200 each year.
The child trust fund provides £250 for all children at birth and age seven, with an additional £250 for children in lower-income families.
Christine Lenehan, director of the Council for Disabled Children, said the extra funding was unexpected.
"To get any money in a budget we expected to be tight shows a continuing commitment from government to disabled children," she said.
"The money, and the message it gives, is really important to families. Children with very profound impairments are surviving into adulthood in numbers never seen before.
"This means they will have money set aside that can be supported by additional contributions."
Srabani Sen, chief executive of Contact a Family, said: "This extra money through the child trust fund payments is a significant boost as it is going to be paid annually. This will mean disabled children getting significantly more than other children although it doesn't benefit them now, when they need it most."
