Effects of cold work on hydrogen diffusivity, hydrogen concentration and hydrogen trap density in AISI 430 stainless steel were investigated. Hydrogen concentration and trap density were increased with increasing cold work, but diffusivity was decreased. The increase in trap density as a result of cold work was responsible for the decrease in hydrogen diffusivity and the increase in hydrogen concentration. Trap densities varied from 10(21) cm(-3) for the cold-worked specimen to 10(17) cm(-3) for the annealed. The cold-worked steel was more sensitive to hydrogen-induced blistering due to its higher hydrogen concentration and trap density, but no blistering was found on annealed specimens. (C) 2003 Elsevier Science B.V. All rights reserved.