The group In Defense of Animals says the killing of dogs for food in Korea increases in August because of the popularity of a summer stew. Protestors held up images of caged dogs that they say are brutally killed.
"Dogs are tortured before being killed, one of the reasons for this is this perverse belief, according to South Korean activists, that the more a dog is tortured, the better the taste," In Defense of Animals spokesperson Robin Dorman said.
The group wants the Korean government to enforce a law that bans the sale of dog meat.
The Korean consulate in San Francisco did not want to comment on the issue.
One-third of Koreans say they have tried dog meat, but only a small number eat it regularly.