The former soldier has ruled for 13 years and is leading in the polls ahead of the general election. He has vowed to win a new six-year term despite undergoing cancer surgery last June.
Here are some key facts about Chavez:
* Born to a poor family in the Venezuelan plains, or "llanos," on July 28, 1954, Chavez once aspired to be a painter and then a professional baseball player. He often explains politics using baseball metaphors and the folksy language of the llanos he learned during his childhood.
* A former lieutenant colonel, Chavez spent much of his later military career conspiring with other leftist officers to overthrow the traditional political order. He led a 1992 coup that failed but made his reputation and propelled him toward the presidency.
* Chavez won a 1998 presidential election and took office early the following year. Opposition politicians and dissident troops led a coup against him in 2002, but supporters and loyal soldiers swept him back to power in less than two days. Chavez accuses the U.S. government of backing the putsch.
* Chavez has enjoyed wide backing among Venezuela's poor majority with massive social spending to expand health and education programs, financed by income from oil exports. He has also cultivated support by confronting the United States, which he denounces as a decadent empire.
* He first warned in 2004 that he would shut off oil supplies to the United States if it tried to invade the Andean nation or impose a trade blockade against his country -- after he accused then U.S. President George W. Bush of backing the short-lived 2002 coup attempt. The following month, he backed away from the threat and said he did not have any intention of damaging relations with Washington.
* Inspired by his friend and mentor, Cuba's Fidel Castro, Chavez has taken Venezuela down an increasingly radical path, nationalizing large swathes of the economy and running the government with a personalized -- many say autocratic -- style. Opponents say he has become an old-style Latin American "caudillo," or dictator, repressing critics, squandering the nation's oil wealth and ruining its economy.
* Chavez has a deliberately populist style and is famous for his strong language and long-winded speeches that often drag on late into the night. He recently broke his own record to give a speech for 9 1/2 hours.
* Chavez announced in June that he was being treated for cancer. He had an initial operation in Cuba to remove a pelvic abscess on June 10. That was followed by the more serious cancer tumor surgery.
* Since then he has had three chemotherapy sessions in Cuba and one in Venezuela. He says he is feeling better than ever and that his doctors have found no new cancer cells.
* While still combative and dismissive of his political rivals, the cancer treatment has made Chavez change his habits and diet, his governing style and even his outlook on life. He is more philosophical, frequently invokes God and has toned down his punishing lifestyle and work schedule.
(Reporting by Caracas newsroom; Editing by Kieran Murray and Sandra Maler)
