Iskra (Spark) was first published by the Social Democratic Labour Party in December, 1900. Edited by George Plekhanov, Vladimir Lenin and Jules Martov, it was printed in Munich and then smuggled into Russia by a network of SDLP agents. It was the first underground Marxist paper to be distributed in Russia and was later printed in Leipzig, London and Geneva.

The editorial board included George Plekhanov, Pavel Axelrod, Vera Zasulich, Vladimir Lenin, Leon Trotsky and Julius Martov. After the split with the Bolsheviks in 1903, Iskra came under the control of the Mensheviks.