Glasspool's ordination was "joyful and well attended"
The US Episcopal Church has ordained an openly lesbian bishop in a move likely to increase the turmoil in the Anglican Communion.
Saturday's ordination came despite warnings from the Archbishop of Canterbury that it would deepen an already bitter dispute on sexuality.
Mary Glasspool, 56, became an assistant bishop at a ceremony attended by 3,000 people in Long Beach, California.
Gene Robinson became the first openly gay US bishop in November 2003.
BBC religious affairs correspondent Robert Pigott says that since then the Anglican Communion has been on course for a permanent split.
Mary Glasspool was ordained with another woman bishop, Rev Canon Diane Jardine Bruce.
Both were elected last December and become the first two women bishops in the Diocese of Los Angeles's 114-year history.
Church spokesman Bob Williams said that those attending burst into applause after the ordination.
"The event was joyful and well attended," he said.
The election of Mary Glasspool - who has been with her partner Becki for 22 years - represented a snub by the liberal Episcopal Church to other Anglican Churches around the world, our correspondent says.
Archbishop of Canterbury Rowan Williams had urged the American Church not to proceed with the ordination, warning that it would further alienate traditionalists who believe active homosexuality to be a sin.
Our correspondent says the latest ordination is likely to accelerate the gradual marginalisation of the Episcopal Church within a two-tier Communion and increase tensions between Anglicans elsewhere.
Gene Robinson was elected as the first openly US gay bishop in November 2003 in New Hampshire.
The Episcopal Church at first agreed to suspend the creation of gay bishops but reversed that decision last July.