The crowd of about 500 was called out by Lopez's wife, Lilian Tintori, for a march that ended in Jose Marti square in the capital.
"If you want Leopoldo to stop his hunger strike, set a date for the elections," Tintori told the crowd yesterday, in remarks aimed at socialist President Nicolas Maduro.
Venezuela is due to hold midterm elections in 2015, but no date has been set. Maduro has insisted the vote will go ahead as it is required.
Critics charge that he is trying to delay until the last possible minute to undercut the opposition.
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Lopez, who leads the Voluntad Popular (Will of the People) party, went on his hunger strike demanding that the election date be set and that international monitors be in place.
Lopez, 44, has been held at a military prison outside Caracas since he was arrested in February 2014 on charges of inciting the violence that killed 43 people and wounded hundreds as Venezuelans protested against Maduro's government last year.
Maduro has rejected criticism of his hardline approach towards his opponents and blamed the country's deteriorating economy on the United States.
Venezuela is also the world's second deadliest country in the world, according to UN data.