14 September] 1874 – 18 May 1949), was a revolutionary, Soviet statesman and academic who became People's Commissar of Public Health in 1918, and served in that role until 1930.

Nikolai Semashko was born to a teacher in the village of Livenskoe in Yelets uyezd of Oryol guberniya (in present-day Lipetsk Oblast).

In 1891, after graduating from the Yelets gymnasium (where he studied with Mikhail Prishvin), Semashko entered the medical faculty of Moscow University.

The Swiss police arrested him after Olga (Sarra) Ravich, convicted in the case of the 1907 Tiflis expropriation, sent him a letter from prison.

In 1913 Semashko participated in the social-democratic movement in Serbia and in Bulgaria; at the beginning of World War I he was interned[by whom?].