With electricity intermittent at best and the country's ports under blockade, experts are fighting to save the 12 mummies in the face of heat, humidity and a lack of preservative chemicals.
Some of the remains, from pagan kingdoms that ruled the region around 400 BC, still have teeth and strands of hair.
"These mummies are tangible evidence of a nation's history," said Abdulrahman Jarallah, head of the archaeology department at Sanaa University, but "even our mummies are affected by the war."
"Mummies need a suitable, controlled environment and regular care, including sanitisation every six months," he told AFP.
"Some of them have begun to decay as we cannot secure electricity and the proper preservative chemicals, and we're struggling to control the stench."
"We're concerned both for the conservation of the mummies and for the health of those handling them," Jarallah said.
The mummies are among a host of priceless ancient remains threatened by conflicts across the region.
From Syria's Palmyra to Libya's Leptis Magna, millennia-old historical remains face looting and destruction in various parts of the Middle East.
The Islamic State group systematically demolished pre-Islamic monuments in Syria and Iraq after seizing swathes of both countries in 2014, looting and selling smaller pieces on the black market to fund their rule.
Swiss authorities last year seized cultural relics looted from Yemen, Syria and Libya that had been stored in Geneva's free ports -- highly secured warehouses where valuables can be stashed tax-free with few questions asked.
- Supplies, experts needed -
Old Sanaa, inscribed on UNESCO's World Heritage List since 1986, faces other dangers.
Perched 2,300 metres (7,500 feet) up in Yemen's western mountains, it has been continuously inhabited for over 2,500 years and is home to some of the earliest Islamic architecture.
With more than 100 mosques and 6,000 houses built before the 11th century, the old city is famed for its multi-storeyed homes of red basalt rock, with arched windows decorated with white latticework.
But months after a Saudi-led coalition intervened against Iran-backed Huthi rebels in March 2015, UNESCO added the ancient city to its List of World Heritage in Danger.
In June that year, a bombing in the old city killed five people and destroyed a section including several houses and an Ottoman fort.
Witnesses blamed an air strike by the Saudi-led coalition on the rebel-held capital.
No party has claimed responsibility for the strike.
The coalition has also imposed an air and naval blockade on Huthi-controlled Red Sea ports that are crucial entry points for food and aid.
The UN estimates 60 percent of Yemen's population is at risk of famine.
Yemeni archaeologists have appealed to both local authorities and international organisations to help preserve Yemen's mummies by easing the flow of supplies and personnel.
"We can already see the mummies suffering the effects of a long period of not having been properly maintained," Sanaa University Museum restoration specialist Fahmi al-Ariqi told AFP.
"We need supplies and experts in this sort of maintenance to work with us to save the 12 mummies here at the university, as well as another dozen at the National Museum in Sanaa."
But while those calls have gone unanswered, Yemen's archaeologists remain confident that their heritage can be saved.
"Yemen is full of archaeological sites and mummified remains that are still undiscovered," said Jarallah.
"Our culture, our history, will never disappear."
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