The former top Soviet officials appeared together in public for the first time in 10 years at a news conference in Moscow on Wednesday.
They denounced "the destruction of the country," and said they were ready to "mount the barricades" again to restore the Soviet Union.
Coup leader Gennady Yanayev - a former Soviet vice-president who proclaimed himself acting president of the USSR - said he would gladly do it all over again.
"All my comrades gathered here are true patriots, defenders of the state - I'm proud to have joined them in their battle to defend the Soviet Union and its long suffering people," he said.
The coup lasted only two days and the plotters were later sent to jail, labelled traitors. They were granted an amnesty in February 1994.
Their coup paved the way for the dissolution of the Soviet Union in December 1991.
Unrepentant
The BBC's Steven Rosenberg in Moscow says the plotters lined up just like they did in 1991, when they announced that Mikhail Gorbachev was sick and they were forming an emergency committee to run the country.
He says the surroundings were not the most auspicious this time - a tiny office of the newspaper Patriot in a crumbling Moscow block.
Dmitry Yazov - a former defence minister - said that in the decade since the dramatic events of 19-21 August 1991, "the political system, the economy and the army have been wiped out, along with the moral purity of the Russian people".
Another of the plotters, Oleg Baklanov, listed what he saw as the country's present ills.
"Wars in the former Soviet republics, refugees, children left alone, tuberculosis, Aids and prostitution - that is the result of the presidency of Gorbachev and Boris Yeltsin," he said.
"The current leadership is making efforts to restore control over the country," said former Soviet Prime Minister Valentin Pavlov. "Today they are trying to do what we attempted to do in the Soviet Union in 1991."
Short-lived coup
On 19 August 1991, the coup plotters announced that President Gorbachev was ill, isolated him at a Black Sea resort and put themselves in charge.
They moved armoured columns in Moscow, but stopped short of using force against thousands of protesters who rallied behind Boris Yeltsin, at the time the president of the Russian Federation.
Vyacheslav Generalov - the secret service agent charged with keeping Mr Gorbachev under house arrest - outlined why he thought the coup lacked popular support.
"The only reason people didn't support us is that they'd been hypnotised, turned into zombies. But history's shown that we were right to do what we did."
Despite all the opposition, at least one member of the group - Valery Varennikov - still believed the coup could have been a success.
"If we'd only been firmer, stuck to our guns, then everything would have been OK. But at least we showed Gorbachev that we opposed his policies," he said.
Our correspondent says the plotters still consider themselves the heroes - true patriots who fought to save the Soviet Union. Their only regret, he says, is that they failed.