Stress corrosion cracking (SCC) behaviour of three grades of nickel-substituted manganese stainless steels have been studied at room temperature in 1 M HCl under constant load at different applied potentials. Repassivation studies have also been carried out using a scratching electrode technique. Selective dissolution and film formation similar to that of films formed on alpha brass in ammoniacal solutions, were found to induce SCC in manganese stainless steels. With decrease in nickel content, these alloys were found to be highly susceptible to SCC.