Objective: Falls and related injuries remain a considerable health risk for in-patients. Numerous studies link falls with nurse staffing levels, but the results are inconsistent. The purpose of this study was to explore the associations between fall prevalence and injurious falls on medical wards and three unit-level system factors: daily nurse staffing, patient turnover, and safety climate. Methods: Using a cross-sectional design, we conducted a secondary data analysis of data from the Patient Safety and Falls Project. Five medical units in a Swiss university hospital were included, resulting in a data set of 949 days, with daily measures of nurse staffing, patient turnover and falls. The safety climate was measured using a subscale of the Safety Attitudes Questionnaire and analyzed at the unit level including data from 154 nurses. Robust multivariate logistic regression was used to explore nurse staffing, patient turnover, and safety climate's associations with in-patient falls and fall injuries. Results: After controlling for patient age, length of stay and nursing fulltime equivalents, registered nurse experience showed a significant negative relationship with falls (OR = .83, p < .0001). Patient turnover and safety climate were not significantly associated to falls or fall injuries. Conclusions: By linking nurse staffing variables to in-patient falls and fall injuries, the current study's findings partly confirm those of previous research. Further investigation will be necessary to isolate key factors influencing the association at the unit level between safety climate and in-patient falls.