It has been a bad few weeks for South Koreans.
Last month, 300 passengers - mostly students - died in a ferry disaster.
On Monday, seven people were killed and 20 injured in a fire at a bus terminal in Goyang city, South Korea.
Yesterday, there was more tragic news when a blaze at a nursing home killed 21 and injured eight.
Most of the patients were in their 70s and 80s and had Alzheimer's, stroke or chronic diseases, officials said.
A patient suffering from dementia is suspected of starting the fire.
Bloomberg quoted a police officer as saying that an 81-year-old patient is under investigation.
A police officer said they found a cigarette lighter at the scene and forensic experts are examining it.
The incident happened at an annex of the Hyosarang hospital in Jangseong, about 280km south of the capital Seoul.
The fire was put out quickly, but by then the damage was already done.
"The number of victims is large because the patients were sleeping and most of them have problems moving due to senile illnesses including Alzheimer's," said Mr Park Yong Gu, an official at the region's emergency services control centre.
"We managed to prevent the fire from extending to the larger next-door building that holds 245 people."
A director of the hospice, Mr Lee Hyung Seok, apologised, BBC reported.
He told reporters: "I've committed a grave sin... There is no excuse when valuable lives were sacrificed."
Mr Kim Jeong Bae, one of the firefighters who entered the building, which was engulfed in black smoke, said that none of the bodies that he and his colleagues retrieved was burned.
The victims were apparently already dead when firefighters went in.
South Korean media including Yonhap news agency had earlier reported that some of the dead patients had their hands bound to their beds.
The reports did not cite a source for the information.