Background: Hospital inpatient falls are common and may lead to injuries and prolonged hospitalization. Although hospital studies have reported overall fall rates and injuries associated with falls, few have addressed population characteristics and circumstances of falls across clinical departments within a hospital setting. Objective: To determine inpatient fall rates in an urban public hospital and to explore associated characteristics across clinical departments. Methods: The study was conducted in a 300-bed urban public hospital in Switzerland from 1999 to 2003. Patient data and data from the hospital’s standardized fall reporting system on hospital inpatients’ first falls, along with associated characteristics, across the departments of internal medicine, geriatrics and surgery, were analyzed. Descriptive statistics and statistical tests: χ2 and ANOVA tests with multiple comparisons tests (post-hoc analysis) were used. Results: Over this 5-year period, 34,972 patients were hospitalized (female 53.6%; mean age 67.3 ± 19.3 years; mean length of stay 11.9 ± 13.2 days) including 2,512 patients (7.5%) who experienced at least one fall during their hospitalization (geriatrics 24.8%; internal medicine 8.8%; surgery 1.9%). The fall rates per 1,000 patient (adjusted for age) days differed significantly between all of the departments (geriatrics 10.7; internal medicine 9.6; surgery: 3.2) (p < 0.001). Overall, 30.1% of the patients who fell experienced minor injuries and 5.1% major injuries. In geriatrics, fall-related circumstances such as transferring were more common (40.4%) than in medicine (33%) or surgery (30.4%) (p < 0.001), whereas falling out of bed was rarer (16.4%) (surgery 27.1%; internal medicine 20.5%) (p < 0.001). In addition, the prevalence of risk factors among patients who fell varied significantly among clinical departments, except for impaired cognition and narcotic use. Conclusion: In the hospital studied, inpatient falls are significantly more common in departments of geriatrics and internal medicine than in surgical departments. Fall rates, related injuries and circumstances of inpatient falls varied significantly among clinical departments, probably due to differences in patient characteristics. When monitoring falls, hospitals should therefore consider differences in characteristics associated with patient falls across clinical departments. High priorities should be allocated in view of identifying patients at risk of falling and implementing fall prevention strategies and interventions.