10 January] 1775) was an ataman of the Yaik Cossacks and the leader of the Pugachev's Rebellion, a major popular uprising in the Russian Empire during the reign of Catherine the Great.

In 1770 he deserted the Russian military and spent years as a fugitive, gaining popularity among the peasants, Cossacks and Old Believers against a backdrop of intensified unrest.

Claiming to be Catherine's late husband Tsar Peter III, Pugachev proclaimed an end to serfdom and amassed a large army.

[3] Dispatched to Cherkassk for investigation, he met Lukyan Ivanovich Khudiakov, whom he tricked into releasing him, after which he fled to Vetka, a Polish border settlement, with the help of many raskol'niki.

[7] Pugachev, posing as a wealthy merchant, reportedly tested the feelings of the Cossacks at the Yaitsk by suggesting that he led a mass exodus into Turkey.

[9] By promising to return several privileges to the Cossacks and to restore the Old Belief, he was able to gain the support he needed to promote his identity as Peter III.

[10] The story of Pugachev's strong resemblance to the Tsar Peter III, who in 1762 was overthrown and murdered by his wife's supporters, the future empress Catherine II, comes from a later legend.

[11] Having amassed an army through propaganda, recruitment and promise of reform, Pugachev and his generals were able to overrun much of the region stretching between the Volga River and the Urals.

As well as amassing large numbers of Cossacks and peasants, Pugachev also acquired artillery and arms and was able to supply his force better than the Russian army would have predicted.

[12] In response, General Peter Panin set out against the rebels with a large army, but difficulty of transport, lack of discipline, and the gross insubordination of his ill-paid soldiers paralysed all his efforts for months, while Pugachev's innumerable and ubiquitous bands gained victories in nearly every engagement.

Not until August 1774 did General Michelsohn inflict a crushing defeat upon the rebels near Tsaritsyn, when they lost; ten thousand were killed or taken prisoner.

The village (stanitsa) in which Pugachev was born, whose original name "Zimoveyskaya" was changed after his defeat to Potemkinskaya, was renamed Pugachevskaya in his honor in 1917, following the October Revolution.