Thousands of protesters marched through the streets of Santiago. Crowd size estimates ranged from 25,000-50,000. Protests also took place in Valparaiso and Concepcion.
Most of the marches passed peacefully but a police kiosk was on fire in one incident.
Student protests against high tuition fees and other costs of education began last year and have galvanized public opinion, posing a wider political challenge to Pinera and denting his approval ratings.
Chilean education is one of the most expensive in the world, with up to 40 percent of education spending borne by families rather than the state. Critics say the education system has created a class system with the wealthy elite leading a majority of underprivileged students struggling to continue their classes.
Pinera won the presidential vote in January 2010 on a pledge of moving Chileans into the 21st century with wide-ranging reforms and economic and social modernization.
Shortly before he took office, Pinera's plans were thwarted by a magnitude-8.8 earthquake on Feb. 27, 2010, that caused several billion dollars worth of damage. Pinera ordered reconstruction but progress has been patchy and slow.
The education inequalities condemned by students, labor and teacher unions weren't high on Pinera's agenda even after early protests combined with other economic demands. When protests intensified last year, some analysts said the unrest appeared to threaten Pinera's political survival.
Student and labor unions accused law enforcement agencies of brutality and summary arrests.
The president now wants to raise taxes -- up to $700 million -- to pay for ambitious education reforms.
Pinera appeared on national television Wednesday to outline the tax reforms and his plans to funnel the proceeds into reforming the education system.
"Thanks to these measures no young Chilean will ever again be excluded from higher education because of a lack of resources ... This is something that fills me with pride," Pinera said.
His critics say the president damaged his credibility by not taking an initiative on glaring inequalities in the education system.
The government also proposed measures to reduce the interest rate on student loans from 6 percent to 2 percent but students and their supporters in other parts of the economy say Pinera needs to do more.
The student and labor unions have said the protests will continue until Pinera comes up with convincing proposals for education reforms.