A 53-year-old man in Mukdahan, in eastern Thailand, died after contracting anthrax, according to the provincial health office.
This is the first human anthrax death reported in Thailand since 1994, prompting a public health alert in the province.
A second case was confirmed in the same province and three additional suspected cases under investigation, officials report.
Thailand last reported human anthrax cases in 2017, when two people were infected without fatalities.
Authorities have identified at least 638 people as being potentially exposed after eating raw meat. Among them, 36 had participated in butchering livestock while the rest had consumed raw or undercooked beef, health officials said.
All are receiving antibiotics (doxycycline) as part of containment measures.
The Agriculture ministry reports a 5 km quarantine zone has been established around the infection site with plans to vaccinate more than 1,000 cattle.
Anthrax is a serious infectious disease caused by gram-positive, rod-shaped bacteria known as Bacillus anthracis. Anthrax can be found naturally in soil and commonly affects domestic and wild animals around the world. Although it is rare, people can get sick with anthrax if they come in contact with infected animals or contaminated animal products.