<$O_ST_ABS>Objective<$C_ST_ABS>Many changes have been initiated in the Dutch hospital sector to optimize health-care delivery: national agenda-setting, increased competition and transparency, a new system of hospital reimbursement based on diagnosis-treatment combinations, intensified monitoring of quality and a multi-layered organizational development programme based on quality improvement collaboratives. The objective is to answer the question as to whether these changes were accompanied by a further development of hospital quality management systems and to what extent did the development within the multi-layered programme hospitals differ from that in other hospitals. <$O_ST_ABS>Design<$C_ST_ABS>Longitudinal data were collected in 1995, 2000, 2005 and 2007 using a validated questionnaire. Descriptive analyses and multi-level modelling were applied to test whether: (1) quality management system development stages in hospitals differ over time, (2) development stages and trends differ between hospitals participating or not participating in the multi-layered programme and (3) hospital size has an effect on development stage. <$O_ST_ABS>Setting<$C_ST_ABS>Dutch hospital sector between 1995 and 2007. <$O_ST_ABS>Participants<$C_ST_ABS>Hospital organizations. <$O_ST_ABS>Intervention<$C_ST_ABS>Changes through time. <$O_ST_ABS>Main Outcome Measure<$C_ST_ABS>Quality management system development stage. <$O_ST_ABS>Results<$C_ST_ABS>Since 1995, hospital quality management systems have reached higher development levels. Programme participants have developed their quality management system more rapidly than have non-participants. However, this effect is confounded by hospital size. <$O_ST_ABS>Conclusions<$C_ST_ABS>Study results suggest that the combination of policy measures at macro level was accompanied by an increase in hospital size and the further development of quality management systems. Hospitals are entering the stage of ...