Abstract Background A growing body of evidence supports the link between hospital organisational culture and health outcomes. Organisational culture is thus an essential consideration for hospital accreditation, a practice of systematically assessing the quality of hospital care against accepted standards. This study assesses the interplay between accreditation and hospital professional staff perception of organisational culture. Methods A prospective cohort study design was used to explore the influence of accreditation on organisational culture within a large, publicly-funded, university teaching hospital in Hong Kong. All full-time hospital and academic physicians, nurses and allied health professionals were invited to participate. Organisational culture was evaluated using the Competing Values Framework through the Quality Improvement Implementation Survey. Organisational culture was assessed longitudinally at 9 months prior to accreditation, 3 months following and 15â months after accreditation. To capture potential shifts in staff perception of organisational culture through the accreditation process, we conducted a between time-point comparison using a linear trend model. Results 545 clinical staff completed the organisational culture survey pre-accreditation, 378 three- months post-accreditation and 141 15-months post-accreditation. Hierarchical culture was the dominant organisational culture domain pre-accreditation, followed by rational, developmental and group culture, respectively. Following accreditation, hierarchical culture declined but remained dominant, while group and developmental culture increased. However, the decline in hierarchical culture was U-shaped with scores increasing at 15-months post-accreditation, though not to pre-accreditation levels. When stratified by professional group, hierarchical culture declined following accreditation with corresponding increases in group culture and developmental culture among physicians and nurses, respectively. While allied health professionals did not perceive any significant cultural differences directly following accreditation, a significant increase in hierarchical culture and corresponding decrease in group culture was found 15-months post-accreditation. Conclusions This study suggests the hospital accreditation process may contribute to shifts in staff perception of organisational culture. Our findings also indicate differential views of organisational culture across professional groups. Finally, we note the striking dominance of hierarchical culture in this Hong Kong hospital across all time points, far surpassing other studies, even those in which hierarchical culture prevailed.