From April '97 to June '97 a round robin test on accelerated life time testing of absorber coatings was performed by three different laboratories. This investigation was undertaken within a project of the working group 'Materials in Solar Thermal Collectors (MSTC)' of the International Energy Agency - Solar Heating and Cooling Programme (IEA - SHCP). The tests where performed according to the standard proposal 'Solar Energy - Materials for Flat Plate Collectors - Qualification Test Procedures for Solar Absorber Surface Durability' (1), which was submitted to the secretariat of ISO TC 180 'Solar Energy' in February 1997. The proposal is basing on a methodology for accelerated life-testing of solar absorber coatings developed within the framework of the former IEA SHCP Task X (2) and was refined by the IEA working group MSTC. In all, five different absorber coatings were available for the round robin. Three of them are of the black chromium type (two on copper substrate one on stainless steel). One is a new sputter coating on stainless steel and another is a selective paint on an aluminium substrate. The examination performed by all three laboratories are the check of the optical homogeneity followed by the tests of the resistance to thermal loads as well as to high humidity & condensation. The results of the different labs show very high agreement for all of the tests and for all of the coatings.