Fractographic characteristics of hydrogen embrittlement in AISI type 316, 321 and 347 austenitic stainless steels was studied by charging thin tensile specimens with hydrogen through cathodic polarization. Throughout this study, we compared solution-annealed samples of various austenite grain sizes with samples given an additional sensitization treatment. Room temperature cathodic charging of unstressed specimens produced intergranular and secondary transgranular cracks along crystallographic planes. The results showed that a finer grain size improved the resistance to hydrogen cracking regardless of the failure mode. Examination of the fracture surfaces of coarse-grained specimens tested while cathodically charged showed considerable differences between the annealed and the sensitized specimens. Finally, the microstructures were related to various modes of cracking.