The former government of Valentin Pavlov was dissolved following the failed August Coup against Mikhail Gorbachev and his supporters. Ivan Silayev took over the office of the Premier. The government was dissolved when Silayev, along with Gorbachev, officially resigned from their own respective posts on 26 December 1991 when the Soviet Union was formally dissolved.
References
Silayev's Government Wikipedia(Text) CC BY-SA