Roman Catholic dioceses and religious orders received nearly 600 credible clergy sex abuse claims last year.
All but a few of the allegations involve wrongdoing from decades ago that are only being reported now.
The findings released Tuesday are part of an annual child safety report commissioned by the U.S. Conference of Catholic Bishops.
Auditors check compliance with the discipline plan bishops adopted in 2002 at the height of the abuse scandal.
Church officials say they paid more than US $144 million in settlements and related costs last year, a slight drop from 2010.
Another US $33 million was spent on background checks and other child protection measures.
Auditors say improvements are needed in how dioceses monitor accused priests.
The auditors also warn about complacency after a decade of intense scandal.