Objectives: The purpose of this study is to explore patient safety culture differences in 90 Belgian acute hospitals; to understand workers' perceptions of safety culture and ways in which culture varies among hospitals and by work area and discipline. Furthermore, we wish to check if there are individual, unit or hospital related factors influencing differences in safety culture. Research Design: The Hospital Survey on Patient Safety Culture (HSPSC) was distributed organization-wide in 180 Belgian hospitals participating in the federal program on quality and safety between 2007 and 2009. The HSPSC measures safety culture on 12 dimensions, including ten safety dimensions and two outcome dimensions, and is designed to measure staff perceptions on patient safety issues, medical errors and event reporting. The scores were expressed as the total and average of positive answers towards patient safety for each dimension. Only the outcome dimension 'over all perception of patient safety' has