The success of Italian movements opposing the war in Iraq during the period 2003–2005 has awakened historians’ interest in the historical features of left-wing pacifism in Italy. Some particularly noteworthy contributions have focused on the campaigns orchestrated around 1950 by the Italian Committee of the Partisans of Peace (the international movement financed and supported by the USSR and international communism against Western anti-Soviet rearmaments). After describing the principal features of existing research, this article focuses on the lexical and communicative aspect characterising left-wing pacifism in Italy in the years immediately following the Atlantic Treaty. It highlights the way in which communist and socialist language gravitated towards the classist and anti-capitalist definitions of ‘war’ and ‘peace’, in line with the position developed in Lenin's reflections in Imperialism, the highest stage of capitalism. However, in the same context, there were images and symbolic references imbued with a rebuttal of the violence of war but with fewer ideological connotations, which reflected an attempt to attract the interest and support of groups and individuals ideologically distant from Marxism. This interweaving of choices of expression contributed to the deep-rooted influence of left-wing pacifism within Italian cultural politics.