More than 300 firefighters were battling the flames, which had spread several kilometres along hilly ground behind the coast, and 31 planes and helicopters were dumping water on the blaze.
Millions of tourists visit the Costa del Sol, famed for its beaches and nightlife, every year and hundreds of thousands of expatriates from northern Europe live on the coastal belt.
"The fire is horrific, with flames 10 to 15 metres high," Angel Nozal, the mayor of Mijas, an inland town between Marbella and Malaga, told the national daily El Pais.
The charred body of an elderly man was found in Ojen, north of Marbella, and a man and a woman in their fifties were taken to the city's Costa del Sol hospital after suffering serious burns, the regional government of Andalusia said.
The fire broke out on Thursday near the port city of Malaga and raced westward through tinder-dry hilly countryside, fanned by strong winds and high temperatures.
Thousands of people had to be hurriedly evacuated to a sports centre when the fire reached housing estates on the outskirts of Marbella. Two roads near the city were closed because of the fire but authorities said one had been reopened.
A 40-year-old mother and her two children were receiving hospital treatment for minor injuries after hiding in caves to escape the fire in Ojen, a town in the mountains behind Marbella.
"This is without a doubt the worst fire we've had in Malaga," Elias Bendodo, President of Malaga Council, told Spanish national radio.
"Thousands of people have been evacuated ... Two people are definitely injured and ... lots of houses have suffered damage," he said.
Unusually dry weather in Spain has resulted in wildfires burning thousands of hectares of land this summer, and temperatures have hit record highs in some regions.
Thousands of people were evacuated earlier this month in the Canary Islands, while four people died in fires in the border area between France and Catalonia, in northeast Spain, in July.
