A further one million children are at risk of famine in Yemen, Save the Children has warned.
Rising food prices and the falling value of the Yemeni currency as a result of the conflict are putting more families at risk of food insecurity.
But another threat comes from fighting around the key port city of Hudaydah, which is the entry point for most aid to the country's rebel-held areas.
The charity says a total of 5.2 million children in Yemen now face famine.
Why is there a war in Yemen?
Yemen has been devastated by a conflict that escalated in early 2015, when Houthi rebels seized control of much of the west of the country and forced President Abdrabbuh Mansour Hadi to flee abroad.
Alarmed by the rise of a group they saw as an Iranian proxy, the UAE, Saudi Arabia and seven other Arab states intervened in an attempt to restore the government.
What impact has this had on people?
The war has led to severe delays in paying the salaries of teachers and public servants, with some people receiving no wages for almost two years.
Those who are paid face food prices which are 68% more expensive than when the war began.
Meanwhile, the Yemeni Riyal has lost almost 180% of its value over the same period, according to Save the Children.
Earlier this month, the currency reached its lowest value in history, placing a further burden on population.
Fears also remain of potential damage to or a blockade of Hudaydah's port as a result of the fighting.
The basic supplies that pass through it are needed to prevent famine and a recurrence of a cholera epidemic that affected a million people last year.
What has Save the Children said?
"Millions of children don't know when or if their next meal will come," the chief executive of Save the Children International, Helle Thorning-Schmidt, said.
"In one hospital I visited in north Yemen, the babies were too weak to cry, their bodies exhausted by hunger.
"This war risks killing an entire generation of Yemen's children who face multiple threats, from bombs to hunger to preventable diseases like cholera," she added.
Earlier this month, Save the Children said it had treated almost 400,000 children under the age of five for severe malnutrition so far in 2018, warning that more than 36,000 children could die before the end of the year.
Almost 10,000 people - two-thirds of them civilians - have been killed and 55,000 others injured in the fighting, according to the United Nations.