Design A two-phase prospective intervention study. Objective The objective of this study was to determine if feedback of adenosine triphosphate (ATP) measurements decreases environmental contamination within hospitals in the Dutch/Belgian border area. Methods Standardized ATP measurements were conducted in nine hospitals on pre-defined fomites. Four different fomite groups were defined: medical devices, patient-bound materials, ward-bound materials and sanitary items. ATP results were reported in relative light unit (RLU), RLU >1000 was considered as 'not clean.' Two rounds of ATP measurements were conducted. After the first round of ATP measurements, results were provided to the wards and cleaning staff. The second round of ATP measurements was performed one year later. The amount of surface contamination before and after the feedback was compared. Results In total 1923 ATP measurements were performed. Before feedback 960 ATP measurements were conducted and after feedback 963 were conducted. The overall median reduction in RLU was 381 (P < 0.001), from 568 before feedback to 187 afterward. In each hospital there was a reduction of the median RLU after feedback. Conclusions Substantial reductions in RLU values were found after feedback of ATP measurements. Feedback of ATP measurement in itself was associated with a major reduction of surface contamination in hospitals.