Equipments which operate in wet hydrogen sulfide (H 2 S) environment can be subjected to Hydrogen Embrittlement (HE) damages like Hydrogen Induced Cracking (HIC), Stress Oriented Hydrogen Induced Cracking (SOHIC), or Sulfide Stress Cracking (SSC). The resistance of steels to HIC and SSC is usually evaluated through standard tests (NACE TM0177 and NACE TM0284). These tests give operators and steel suppliers a pass/fail response for a given application. However, the detailed mechanisms of wet H 2 S cracking are not fully understood yet, although a lot of work has been carried out over the years on this subject. In particular it is of interest to better understand the initiation and propagation phases of HIC and SSC. For this purpose, some laboratory studies have used the acoustic emission (AE) technique to monitor the materials behaviour during HIC and/or SSC tests. Most of the results were promising, as some correlations were found between AE parameters and the cracking susceptibility of different materials. However, the most important gap stands in the analysis of AE data, which is always considered as a bulk, without any attempt to separate the contribution of other acoustic sources (such as general corrosion or hydrogen bubbling in the solution) from the cracking itself. A methodology was developed in this work to discriminate HIC signals from other sources. The aim was to isolate the cracking contribution, and compare HIC propagation mode for different non sour service steels. In addition tensile tests monitored by AE on two sour service steels are also presented. Difference between SOHIC and SSC mechanisms could be evidenced by AE.