Most national newspapers took little or no notice of the anniversary, reflecting the deep ambivalence of many Russians about the events that plunged them into both anxiety and exhilaration.
"The victory that we lost," said a headline in the newspaper Moskovskiye Novosti.
The coup attempt was initiated by a coteries of Communist hard-liners who placed Soviet leader Mikhail Gorbachev under house arrest at his vacation home, fearing that his pending agreement to allow wide sovereignty for Soviet republics would lead to the USSR's disintegration.
But wide public opposition quickly weakened the putsch, notably the thousands who gathered around the Russian government headquarters where Russian President Boris Yeltsin famously defied the coup while standing atop a tank.
The coup collapsed three days later and Gorbachev returned to Moscow, but his power and credibility were fatally dissipated. The republics of Estonia, Latvia and Lithuania were allowed to split off from the Soviet Union within weeks, and the entire USSR was signed out of existence in December.
The collapse led to severe economic hardships for tens of millions and to a long period of political chaos and the rise of politically powerful tycoons who became known as oligarchs.
National television channels planned to run documentaries about the period later in the day. In a peculiar reminder of Soviet television practice, the channel Kultura is to broadcast a performance of the ballet Swan Lake - the same performance that state TV showed even as columns of tanks ground through Moscow's streets two decades ago.
Many of those who gathered around the Russian government building to protest the coup 20 years ago were to gather again on Friday evening.
Some politicians took note of the anniversary Friday.
Sergei Mironov, leader of the party A Just Russia, visited the cemetery where three men who died while defending the Russian government building are buried, praising "all those who believed in the necessity of freedom for Russia."
Lower parliament house speaker Boris Gryzlov, in a comment reminiscent of the Marxist belief in the inevitability of historical progress, said the coup plotters were doomed from the start because "they tried to change the course of history."