Moishe Rosen, a controversial convert to Christianity who founded the missionary group Jews for Jesus, died Wednesday in San Francisco. He was 78.

The cause was prostate cancer, the group announced.

Rosen launched Jews for Jesus in San Francisco in 1973 and over the next decade turned it into a flourishing movement that drew thousands of converts from among the youthful seekers of the counterculture era.

Its success stirred the wrath of Jewish leaders, who denounced Rosen as a cultist.

Rosen appealed to potential converts with music, humor and street theater, an approach that resonated in the hippie culture that by the early 1970s was developing a strong spiritual component.

"I never made the decision that I wanted to leave the Jewish community," he told New York magazine in 1986. "We want to stay in and dissent - and we've been ostracized. We wouldn't separate the two religions. We want a climate where all ideas can be accepted or rejected without previous indoctrination."

Born in Kansas City, Mo., on April 12, 1932, Rosen grew up in Denver in an Orthodox Jewish family. He was an undergraduate at the University of Colorado in the late 1940s when he met a young Jewish woman named Ceil Starr. In 1953, three years after they were married in an Orthodox synagogue, she met an evangelical Christian and converted. Rosen soon followed her into the faith.

He gave up his job as a camera salesman to enroll at Northeastern Bible College in New Jersey and in 1957 was ordained as a Baptist minister.

He worked for the American Board of Missions to the Jews for the next 15 years, 10 of which he spent in Los Angeles as minister for several Hebrew-Christian fellowships. In 1967, he moved to New York to direct recruitment and training for the missionary board.

Intrigued by the hippie movement, he returned to California in 1970 and moved to San Francisco, where he began ministering to Jews with the message that they could believe in Jesus without giving up Jewish culture.