The aim of this project was to improve treatment processes and results in acutely ill inpatients within a network of nine psychiatric state hospitals of the Landschaftsverband Rheinland by introducing a benchmarking process. The project was based upon pre-existing measures of quality management. Patient groups were selected that were characterised by a severe clinical development or a high demand for mental health care services (alcohol abuse, depression of the elderly, schizophrenia). Room for improvement concerning specific hospitals and the overall hospital network were identified. The project was conducted with two patient cohorts before and after a quality-related intervention. Interventions were implemented for specific hospitals and the overall hospital network. Overall treatment documentations of 1,696 patients (1(st) cohort n=1,856, 2(nd) cohort n=1,696) were completed. Although there was no constant quantifiable statistically significant improvement of quality within the three patient groups (and certainly not with respect to the overall network), there was successful improvement of essential treatment processes for certain hospitals and the overall network under benchmarking. This was especially relevant where treatment recommendations were concerned. Future projects should focus on the conformance with treatment guidelines by defining both structural and process measures as a starting point and evaluation criterion., (Copyright © 2011. Published by Elsevier GmbH.)