Thousands of Ecuadoreans filled the main avenues in the coastal city of Guayaquil to protest against the policies and governing style of populist President Rafael Correa.
Led by Guayaquil Mayor Jaime Nebot, who is a member of the opposition, demonstrators in Ecuador's biggest city chanted: "Correa out, out!"
Speaking to a crowd stretching down a street, Mr Nebot said the president's economic policies are harmful and threaten to throw the country into turmoil.
He warned against following the path of the socialist-government in Venezuela, where many goods are in short supply and prices are soaring.
"They say that prosperity, the right to prosper, deserves punishment," Mr Nebot said of Mr Correa's administration.
"This country isn't ever going to accept that, because that is not Ecuador, that is Venezuela."
Mr Correa, who trained as an economist and describes himself as socialist of the 21st century, has been president since January 2007 and his current term ends in 2017.
He is widely popular with many Ecuadoreans because of his government's generous social spending.
A surge of protests by his opponents has been seen in Ecuador's biggest cities, including the capital of Quito, Guayaquil and Cuenca.
The unrest was set off by the introduction of two new tax bills, one of which would take up to 75% of inheritances, but the protests have continued after Mr Correa temporarily withdrew the legislation from consideration.
Mr Correa is also criticised by enemies for his confrontational style in dealing with such sectors of society as the church, the press, banks and traditional political parties. Human rights groups have called him intolerant.