Jozef Wesolowski, a former archbishop and Vatican envoy to the Dominican Republic, has died before he could be tried for child sex offences.
He had been taken ill just before the start of his Vatican trial in July.
He was accused of paying for sex with children in the Dominican Republic.
Wesolowski, 66, would have been the first high-ranking church official to be tried on paedophile charges. His case was seen as a test of the Vatican's pledge to stamp out abuse.
Last year, the Pope compared the actions of those who commit such crimes to a "satanic mass".