The charity Save the Children has said one million babies die on the first day of their lives every year.
Premature birth and complications during childbirth, such as prolonged labour, pre-eclampsia and infection, are leading to the large number of babies who die within a day of birth.
But more than half of these deaths could be prevented if every woman and baby had access to expert health care workers, the charity said.
It said that it is "criminal" that so many of the deaths could be averted.
South Sudan was cited as being one of the worst-affected countries.
A new Save the Children report, Ending Newborn Deaths, also states that 1.2 million babies are stillborn each year.
The report calls on leaders from around the world to help end preventable newborn mortality.
More must be done to ensure there are enough skilled health workers to make sure that no baby is born without adequate help, it says.
Every year 40 million women give birth without trained help and in some countries just one in ten women receives assistance during labour.
"The first day of a child's life is the most dangerous and too many mothers give birth alone on the floor of their home or in the bush without any life-saving help," said Justin Forsyth, chief executive of Save the Children.
"We hear horror stories of mothers walking for hours during labour to find trained help, all too often ending in tragedy.
"It's criminal that many of these deaths could be averted simply if there was someone on hand to make sure the birth took place safely and who knew what to do in a crisis.
"These new statistics reveal - for the first time ever - the true scale of the newborn crisis.
"The solutions are well known but need greater political will to give babies a fighting chance of reaching their second day of life."