As church members and their families walked to the church for worship services, protesters chanted "shame on the church," "equal rights" and other slogans at them.
The demonstrators blame leaders of the Church of Jesus Christ of Latter-day Saints for encouraging Mormons to funnel millions of dollars into television ads and mailings in favor of the gay marriage ban, known as Proposition 8.
They want an investigation into the church and whether it should lose its tax-exempt status for engaging in political funding.
"We wanted to let these people know that their tithings - though they may not have known - went directly to support Proposition 8," said one of the protesters, Ryan Smith, as he stood outside the church at 5701 8th Ave. NE.
"There should be taxation on the church, or all lobbying groups should be tax-exempt," he added.
Said another protester, Dikla Tuchman: "I'm out here to support equal rights. I can't believe that in 2008 everybody doesn't have those rights."
The California ballot measure passed Tuesday, which was sponsored by a coalition of religious and social conservative groups, amends the California Constitution to define marriage as a heterosexual act. It overides a state Supreme Court ruling that briefly gave same-sex couples the right to wed.
The protest came amid questions about whether attempts to overturn the prohibition can succeed and whether the 18,000 same-sex marriages performed in California over the past four months are in any danger.