A round robin test on the determination of residual stress depth profiles of shot peered surfaces by X-ray diffraction was carried out within the scope of the BRITS-EURAM project ENSPED (European Network of Surface and Prestress Engineering and Design). 12 ENSPED-partners (8 industrial partners and 4 research institutes) participated in the round robin test. The aim of the test was to ensure the capability of the different partners to determine a residual stress depth distribution properly. Two batches of specimens were manufactured of a heat treatable steel, german grade 42 CrMo 4, - a normalized and a quenched and tempered state. The specimens were shot peened afterwards. In addition to the residual stress values determined by the partners, the raw-data of the measurements were evaluated by one of the research institutes as a reference using a common evaluation software. This evaluation was performed with respect to the individually chosen measurement set-up and the respective measurement parameters. Results will be presented by ensuring the anonymity of the different partners.