President Chavez says the vote is vital to his social spending programmes
Venezuelans have voted in elections to choose new state governors and more than 300 mayors across the country.
The polls are being seen as a critical test for President Hugo Chavez, whose allies won in all but two of the country's 23 states in 2004.
Such a margin of victory is unlikely this time, correspondents say.
Last year Mr Chavez suffered his first electoral defeat in almost 10 years, losing a referendum that would have let presidents seek indefinite re-election.
The opposition is looking to build on that victory.
Mr Chavez enjoys popular support for spending oil wealth on schools, clinics and subsidised food, but needs a resounding win to silence his critics, says the BBC's Will Grant in Caracas.
His government's failure to control crime and inflation are voters' main concerns.
The gloomy outlook for the price of oil - which makes up more than 50% of government income - is also causing concern, while the country has one of the world's highest murder rates and the continent's worst inflation.
Opinion polls suggest Mr Chavez' United Socialist Party of Venezuela (PSUV) is likely to hold most states and cities, but may lose some posts as voters also express concern over corruption and inefficiency.
'Punch in the stomach'
Our correspondent says long queues formed outside polling stations across the country as voting took place in 22 states.
An estimated 140,000 troops were deployed to maintain security, and some 130 international election observers were on hand to help ensure the vote was free and fair.
KEY ELECTION BATTLEGROUNDS
Caracas: Chavez supporter Aristobulo Isturiz against anti-Chavez politician Antonio Ledezma
Zulia state: currently governed by Chavez rival Manuel Rosales
Miranda state: current governor Chavez aide Diosdado Cabello up for re-election
Barinas state: President Chavez's home state. His father, the current governor, is stepping down. His brother Adan standing for the governorship but faces tough election battle
Polls closed at 1625 (2055 GMT) but voters already in line were allowed to cast their ballots.
Analysts on both sides of the political divide say opposition candidates or so-called left-wing "dissidents", opposed to Mr Chavez, may win in a number of states.
Among them are the oil-rich state of Zulia, on the border with Colombia, and the states of Carabobo and Sucre.
Even the president's home state of Barinas - where his brother is the socialist candidate - is in doubt, prompting Mr Chavez to remark that losing in Barinas would be like a "punch in the stomach".
Many people will also be watching the tight battle for the powerful position of Mayor of Caracas.
President Chavez has told voters that a win for what he calls "his candidates" is vital for the future of his popular social spending programmes.
The opposition has tried to counter this by stressing that the vote is not about national projects but local municipalities, in particular the growing problem of civil insecurity and crime.
About 17 million Venezuelans were eligible to vote for 22 governors, 328 mayors and 233 heads of regional councils for four-year terms.