Pelosi, D-San Francisco, will celebrate the new health care reform law Monday at a senior center in San Francisco.
She spoke at the Glide Memorial United Methodist Church Sunday, saying the passage of the legislation will make health care affordable for the middle class and will eventually provide coverage for millions of uninsured Americans.
Congregants filled Glide Memorial to capacity and cheered and applauded throughout her address. The church is known for providing meals, health care and other social services to the jobless or homeless.
Pelosi's comments came after congressional Democrats on Friday sent the final piece of legislation to President Barack Obama. Pelosi, along with other lawmakers, is back in her home district as Congress takes its spring recess.
Pelosi recalled for the crowd the reaction President Barack Obama shared with her on the night he signed the bill. He told her he was more excited that night than on the day he won the election.
She also downplayed concerns that some of her fellow Democrats would be more vulnerable to losing to Republicans when Americans vote in midterm elections this fall.
"What is it that they want to repeal?" said Pelosi. " Under this legislation, no longer will having a pre-existing condition be a reason to deny people health insurance. No longer will being a woman be considered a pre-existing condition."
The president is expected to sign the bill Tuesday.