Around 43,000 people may have died in Somalia last year after several failed rainy seasons, a new report from the Somali government and UN suggests.
It is the first official death toll from the drought in the Horn of Africa. Half of the fatalities are thought to be in children under five.
The crisis is "far from over", with 18,000-34,000 more deaths expected in the first six months of this year.
In 2011, a famine in Somalia killed over a quarter of a million people.
"We are racing against time to prevent deaths and save lives that are avoidable," said World Health Organisation (WHO) representative Dr Mamunur Rahman Malik.
He added that the "cost of our inaction" would mean children, women and vulnerable people would die as "we hopelessly, helplessly witness the tragedy unfold".