On August 17, 1991, to protest the 1991 Soviet coup d'état attempt in Moscow opposing Mikhail Gorbachev's reform program and the new union treaty for decentralizing Soviet power and returning it to the republics, Mamatov joined some of his colleagues in a demonstration in front of the Parliament building and publicly burned his Communist Party membership certificate. He later stood for election as chairman of the Uzbek Journalists Association and claimed that the government falsified the election results.