Background: Inpatient mortality is a critical outcome measure for healthcare services. Improving patient outcomes and ensuring high-quality healthcare outcomes requires an understanding of the factors that contribute to inpatient mortality.

Aim: This study aimed to investigate the impact of safety culture, quality of care, missed care, and nurse staffing on inpatient mortality rates and nurse-reported inpatient death frequency.

Methods: A cross-sectional survey and an administrative dataset on inpatient mortality were used in this study. A web-based survey was conducted among nurses from 34 units in five acute public hospitals. Inpatient mortality data between 2018 and 2021 were collected from participating units. The study variables were analyzed using generalized linear models.

Results: Safety culture scores were less than positive in all hospitals, and most nurses reported missed care during their last shift. However, nursing units that had strong subscale scores for teamwork climate, safety climate, and safety behavior had lower incidence rates of inpatient mortality and fewer nurse-reported inpatient deaths in their units.

Conclusion: The study’s findings highlight the importance of teamwork climate, safety climate, and safety behaviors on safety culture and the role nurses play in reducing inpatient mortality rates and lowering nurse-reported inpatient death frequency.