We report the synthesis of about 90 members of the system La2-xSrxCu1-yRuyO4-delta. Samples were prepared by conventional solid state reactions and characterized by X-ray powder diffraction. We found single phase products adopting the K2NiF4-type structure in the whole range 0 less than or equal to y less than or equal to 1. For a subset of samples Rietveld refinements and thermoanalytical investigations were carried out. The influence of x and y on the structure is discussed. An increasing Sr content was found to cause the formation of some Cu-III/Ru-V. For large x the value of delta increases, leading finally to a breakdown of the structure.