The chanting of 20,000 to 40,000 protesters filled the San Francisco plaza, occasionally punctuated by explosions of dynamite.
Students, street vendors, artisans and the unemployed all answered the Bolivian Union Federation's call to protest a plan to pipe Bolivian gas through Chile for sale to Mexican and US customers.
Labour unions say Bolivia's 18% take is too small.
And they don't trust Chile, which annexed Bolivia's outlet to the sea more than 100 years ago in a war over mineral deposits and bird dropping fertilizer.
Unhappy in La Paz
"Chile - Nation of thieves," the marchers chanted.
''If Goni [the president’s nickname] wants to earn money, he ought to sell his wife,'' chanted several other hundred protesters as they marched through the Mercado Rodriguez street market.
They also called for Sanchez de Lozada's ouster and made fun of his Spanish, which he speaks with a slight English accent.
"The gas should not be sold to Chile. It should be used to industrialise the country, to serve Bolivians", labour leader Jaime Solares told journalists.
Except for sporadic, two week-old roadblocks by protesting coca farmers however, the strike has not created much interest outside of La Paz and has not spread to other parts of the country.
The strike failed to spread outside
The president's chief spokesman, Mauricio Antezana, said: ''They didn't interrupt any sector of the economy.What we saw today is that workers want to work and produce. They don't want to disrupt the country.''
Evo Morales, a member of Congress and the main opposition figure, also recognized that the strike had failed to achieve its goals.
''I said it was a little early to call it,'' he told reporters. “If you're going to organize a strike, you have to be able to carry it out.''
Nonetheless, Morales added, if S?nchez de Lozada decides to export the gas through Chile his government won't last 24 hours.
Economic recovery plan
Economists have said Bolivia's salvation in the coming years lies in a $5 billion plan to export the huge gas reserves - the largest in Latin America after Venezuela's - through the Chilean port of Patillos and then on to the United States, another sore spot for leftists here.
Morales, who just returned from Libya, on Monday called the United States a ''terrorist nation'' for the Iraq war.
S?nchez de Lozada is expected to decide by December whether the gas will be exported through Chile - the only economically feasible route according to the foreign consortium that controls the gas - or through a port in Peru that would cost $1 billion more.
Bolivia is the poorest country in South America but has the second-largest gas reserves in South America.