Venezuela has criticised the outgoing United States' ambassador to the country, saying his three-year term there was a failure.
Earlier this week, Mr Brownfield said he regretted that he had not achieved greater dialogue with the government in Caracas.
He was almost expelled from Venezuela on several occasions.
Mr Brownfield is to be replaced by Patrick Duddy, a top official in the State Department's Latin American department.
Venezuela's Foreign Minister Nicolas Maduro said "there is little to hope" for from any appointee of US President George W Bush.
"We hope the new ambassador who is coming is at least serious and respects Venezuela's sovereignty", Mr Maduro told reporters.
Mr Brownfield said in a televised interview on Wednesday that he felt he made limited achievements in lessening tensions with Venezuela but that he regretted he was not able to establish a pragmatic relationship.
He poked fun at President Chavez's anti-American rhetoric, saying Americans were likely to do "very conspiratorial things" during the Independence Day holiday, such as attending baseball games.
Mr Maduro told reporters that "William Brownfield came to Venezuela with one mission: to destabilize the government of President Chavez, to help topple him. And his mission has failed."
Mr Brownfield took over as ambassador to Caracas in August 2004, and his time was marked by growing hostility between the two governments.
On at least two occasions, President Chavez threatened to expel Mr Brownfield, accusing him of meddling in Venezuela's affairs.
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