UNICEF adds that the 6 million babies a year figure could be doubled if more mothers would breast feed.
The agency blames "lack of awareness amongst mothers, and lack of support from health workers and communities" for keeping the numbers down.
According to UNICEF, 1.3 million lives could be saved each year if mothers would follow its recommendation of exclusive breast feeding up until six months, then complementary feeding for at least two years.
A U.N. official attributes breast milk to a baby's ideal nourishment and disease immunity.
The U.N. reports global breast-feeding rates rose at least 15 percent from 1990 to 2000.
