On a recent Wednesday afternoon, in Siem Reap, Cambodia, professional mixed-martial-arts fighter Justin Wong found himself sparring in a boxing ring with his wife, Jaime Higa, at the Angkor Fight Club, where they’re both regulars. The twenty-eight-year-old Wong held the pads as she lunged at him. Last fall, Higa was offered a job in Siem Reap, a tourist town best known as a jumping-off point for the historic temples of Angkor, and the two decided to relocate here from the Bay Area. Wong, a professional mixed-martial-arts fighter since 2008 who came up through amateur kickboxing in the United States, wasn’t sure, when they made the move, how his cage-fighting career would evolve. “Then I got excited,” Wong said, of his early research. “You don’t need to spend all that money to compete and it’s a small, tight-knit community. It’s been great.”

Today, Wong is part of a slowly but steadily growing M.M.A. scene in Cambodia, the result not only of an influx of expats but of longtime Khmer boxers embracing the sport as a complement to their storied ancient art. Like M.M.A., Khmer boxing—also called pradal serey, and sometimes known, outside Cambodia, as muay thai—is a combat sport in which fighters frequently use their elbows, so the transition from one to the other is fairly seamless. Both inspire aggressive and intense fandom in those who enjoy the brutal, bloody dynamics of the bouts. But while martial arts have ancient roots here—bas reliefs on the walls of the roughly nine-hundred-year-old tombs of Angkor Thom show soldiers engaged in hand-to-hand combat—many organized combat sports, including M.M.A., had, until recently, floundered.

“Sometimes, people ask, ‘Why there are no Khmer coaches my age?’ ” Nicholas Chevdar, the thirty-eight-year-old owner of Angkor Fight Club, said. “It’s because they were all chased out. . . . The coaches my age are virtually nonexistent, because the sport died.” After the United States dropped 2.7 million tons of explosives on Cambodia, during the Vietnam War, the country endured the reign of Pol Pot’s Khmer Rouge, which, from 1974 to 1979, oversaw a genocide that claimed the lives of at least 1.7 million people, roughly a fifth of the nation’s population. According to researchers at Yale University, athletes, including many martial-arts masters, were among those specifically targeted. (The Communist regime saw them as particularly bourgeois.) The Khmer Rouge also killed many who were in its own ranks, including fighters.

Chevdar, who had done some boxing back in the U.S., left New Jersey for Cambodia in 2008. After he arrived, he spent years exploring the local fight scene, which typically consisted of a few locals gathering on dirt patches and practicing on old punching bags. He opened Angkor Fight Club three years ago: one of the first Western- and Khmer-friendly training gyms in the country to offer M.M.A. “Learning the martial art where it all began,” the gym’s Web site proclaims.

Even after Pol Pot fled to his jungle hideaway, in 1979, guerilla warfare, starvation, and land mines made everyday life, let alone organized recreational sports, a difficult proposition. Today, poverty is widespread and access to health care is poor, as a new generation of Khmers rebuilds. Miraculously, Chevdar said, some Khmer boxing techniques were passed down, and today the Cambodian military and local police coördinate recreational fighting clubs and competitions, including Khmer boxing and, more recently, M.M.A. Gyms featuring M.M.A, as well as other combat arts, are growing, chiefly in Cambodia’s largest cities, Phnom Penh and Siem Reap, where a Cambodian middle class has begun to bloom. (Challenges remain: a local gym in Siem Reap, citing financial problems, recently shut its doors, creating further turmoil for those trying to develop the competitive scene.)

Chevdar and other M.M.A. importers soon noticed key differences between the combat sports they were used to in the West and those in Cambodia. It’s not uncommon for some Khmer boxers to fight with dangerous frequency, sometimes as often as weekly or bi-weekly, getting up to three hundred or more fights in a career, with the length of a career varying from fighter to fighter, some engaging in bouts far past their prime. Khmer fighters also tended to be more ambidextrous than their out-of-border neighbors. And many new fighters struggle to deal with the heat here. “You get a bit woozy,” Chevdar said.

There are concerns, too, that, as M.M.A. expands in Cambodia, the corruption that has marred Khmer boxing in the past—consisting not only of match fixing but also child abuse and fighters who received little, if any, medical attention after devastating injuries—will spread in the newer sport. “It’s very gangster,” Chevdar said, of the Khmer boxing scene. Stadiums that have been longtime meccas for fighting tend to have vocal gamblers in the stands, a reflection of the relative lack of gambling laws compared to what pro fighters see in the U.S. “It was almost like a stock floor, because they were yelling these numbers and doing these hand signs everywhere,” Chevdar said. He added, “The Khmer fighters, they’re treated more like meat. When you do the weigh-ins, you see the gamblers there because it’s like they’re eyeing up the horsemeat. They come in to the weigh-ins to check you out.”

“It’s kind of a Wild West here,” Wong said. “But I’ve trained with all sorts of people from around the world. Martial arts is a bit of a universal language.” Cambodian television stations that had embraced Khmer boxing by staging fights in their own studios have begun airing Ultimate Fighting Championship bouts. The Las Vegas-based U.F.C. is the largest M.M.A. promotion company in the world, and these fights helped to create a local fan base for the sport, prompting some people to take it up as participants. “They wanted to do the cage fighting they saw on TV,” Chevdar said. It will likely be years before a Cambodian makes it into the U.F.C., but ONE FC, a Singapore-based circuit, has staged numerous M.M.A. bouts in Cambodia already.

In addition to training, Wong has begun coaching M.M.A. two to three times a week at Angkor, chiefly to expats, but to some Khmer fighters as well. And he’s eager to explore the Southeast Asian circuit. Although Angkor Fight Club is fully equipped with a matted grappling area for mixed martial arts, an M.M.A. ring, a square boxing ring, heavy bags, kick pads, and punch mitts, he will have to travel to Phnom Penh and Bangkok to fight. Fight Club offers M.M.A. classes for kids, but those are more about “using the gym for fun,” Chevdar said, rather than staging real hand-to-hand combat.

After sparring with his wife, Wong greeted three M.M.A. students for a Wednesday night class, then went about showing the three attendees, all expats, a few different attacks. They slid back and forth along black padded mats as a frog hopped nearby and electric fans whirred away the hot night air. With a stereo blaring loud rock music, and the thumping of a fighter hitting a punching bag in the corner, Wong’s charges lunged, thudded, and oofed for an hour before exchanging high-fives. Most of his students are beginners, he said, but that’s part of what excites him. “We get to build something.”