In a tweet, IOM said that no-one was hurt at the health facility, part of the vast Cox’s Bazar camp complex, after the blaze began suddenly on Sunday evening.
Parts of the hospital were badly damaged, but health services are expected to “resume soon”, the agency said.
Field teams have been working around the clock to save the hospital and restore some normality to camp life. They are also assessing the damage and assist those in need.
Pictures posted on social media show charred metal bed frames and workers clearing away piles of ash at the isolation and treatment centre for people with severe acute respiratory infections.
Earlier, IOM teams, Disaster Management Unit volunteers, and Government of Bangladesh response services, rushed to the hospital and worked hard to put out the fire and assist those in need.
The IOM teams are also working to raise awareness amongst refugees about what to do in the case of sudden fire in the camps.
The camp hosts many of the million Rohingya refugees that have fled violence in Myanmar in successive waves of displacement since the early 1990s.
At the peak of the latest crisis, in 2017, thousands were crossing into Bangladesh daily.
Since then, the Kutupalong refugee settlement has grown to become the largest of its kind in the world, with more than 600,000 people living in an area of just 13 square kilometers, stretching infrastructure and services to their limits.
The 2021 Joint Response Plan (JRP) for the Rohingya Humanitarian Crisis targets almost 1.4 million people in need.
The $943 million plan seeks to meet the needs of 884,000 Rohingya refugees and 472,000 Bangladeshis in the host communities of Cox’s Bazar.