Semyon Mikhailovich Nakhimson (pseudonyms: Mikhalchi, Pavel Salin; 25 November 1885 — 6 July 1918) was a member of the revolutionary movement in Russia and military commissar of the Yaroslavl District.

He took an active part in organizing combat squads, issuing revolutionary proclamations, led propaganda among workers and soldiers.

In 1906 he returned to Russia; member of the Kovno military organization of the Russian Social-Democratic Labor Party and the Bund.

In 1912 he returned to Russia and continued working in the organizations of Bund and the Russian Social Democratic Labour Party.

In January 1913, he was arrested in Moscow during the dispersal of an illegal Congress of commercial and industrial employees, which took place on the Sparrow Hills.

From 1915 in the army, he was head of the medical part of an ambulance car, junior doctor of the sanitary unit of the All-Russian Union of Cities, operating on the Southwestern Front.

Thanks largely to his efforts, the 12th Army turned into an uncontrollable mob of deserters, accused of betraying and surrendering Riga to the Germans in August 1917.

In December 1917, the Petrograd newspaper The Day published an article by another famous journalist Lev Lvov about Semyon Nakhimson depicting the unseemly image of a pseudo-revolutionary who allegedly was involved in violations of financial discipline and spreading false information about his biography.

On March 12, 1918 fully rehabilitated by the general meeting of the Executive Committee of the Council of Soldiers' Deputies of the 12th Army, demanding the immediate publication of the decisions of the investigative commission.

On March 22, 1918, on suspicion of withholding 10 thousand rubles during the February retreat, was subjected to house arrest in the city of Rybinsk with suspension from all responsible posts.

He launched an active mobilization work, achieved the formation and sending to the Czechoslovak front of a number of "extraordinary" divisions.

He was killed by a rebel (according to one of the versions he was hacked to pieces at the Bristol Hotel) at the very beginning of the Yaroslavl uprising on July 6, 1918.