Founded in January 1891 at the Congress of Capolago, at which around 80 delegates from Italian socialist and anarchist groups participated. Notable figures included, Errico Malatesta, Luigi Galleani, Amilcare Cipriani, Andrea Costa and Filippo Turati. Malatesta envisioned the PSAR as the Italian federation of a new, anarchist and socialist, International Workingmen's Association.
The PSAR largely fell into the Partito Socialista Rivoluzionario Italiano (PSRI). This organization was a founding member of the Partito Socialista dei Lavoratori Italiani (PSLI) in 1892, which by 1895 had been renamed the Partito Socialista Italiano (PSI) and, amid sectarian struggles, ejected its anarchist wing.