Besides the two bond payments it has defaulted on, Venezuela is overdue on four other debt payments but they were still within the 30 day grace period, S&P said.
In the meantime, China said its massive financing of Venezuela was "proceeding normally", and Russian Federation was expected to sign an agreement as early as Wednesday to restructure $3 billion of Caracas's debt, according to sources in Moscow familiar with the matter.
S&P's verdict came after the Venezuelan government met with global creditors in Caracas but offered no concrete plan for restructuring its $150 billion debt. He insisted, however, the OPEC nation would continue to service its debts.
S&P said it had lowered Venezuela's long-term foreign currency rating to "SD", and cut its long- and short-term foreign currency sovereign credit ratings on the Bolivarian Republic of Venezuela to "SD/D" from 'CC/C.
Instead, the head of the Venezuelan commission, Vice-President Tareck El Aissami, read a statement blaming sanctions imposed by the United States for Venezuela's difficulties in making the payments.
A meeting between Venezuela and its creditors on Monday ended without an agreement to restructure the country's debt, the same day the European Union adopted sanctions over its "political polarisation".
PDVSA, in turn, relies on credit lines from global banks to finance oil production.
The Maduro government had said it would make a $1.2-billion payment on a PDVSA bond on November 2, but it was unclear if the funds ever reached creditors.
Now, as U.S. sanctions cut deeper into what's left of the economy, it's increasingly unclear how Venezuela will support itself.