Mazdoor Kisan Sangram Samiti (Hindi: मजदूर किसान संग्राम समिति, 'Worker-Peasant Struggle Association') was a mass organisation in Bihar, India.

Effectively CPI(ML) Party Unity came to operate as the armed squad of MKSS, confronting the private armies of landlords (senas).

[3] In April 1986 police opened fire on a MKSS rally in Arwal where 23 poor peasants were killed.

One MKSS faction remained loyal to Dr. Vinayan, the other led by Arvind Ji retained links to CPI(ML) Party Unity.

[1] CPI(ML) Party Unity reconstituted its peasant front as the Mazdoor Kisan Sangrami Parishad.