Fifteen people were killed in one mudslide alone on the Pan-American Highway near Guatemala City. According to eyewitness reports Sunday, numerous other people had been buried.
Rescuers searching for survivors also had to contend with new mudslides, media reports said.
Officials said the Pan-American Highway is no longer drivable, as it has been blocked by mudslides in several areas.
At least 24,000 people have reportedly been evacuated. Rains, floods and mudslides have affected 30,000 people in different regions of the country, with 10 rivers threatening to overflow.
The heavy rains have also led to floods in neighbouring Central American countries and in the south of Mexico, killing dozens of people over the last few days. Forty people had been reported dead in Nicaragua by the weekend and 20 in Honduras.