The purpose of the present study was to analyze the determinants of nurse staffing in urban public hospitals in Japan. The study sample included 51 public hospitals in 23 urban cities in 1996. Structural equation modeling was performed using the following: nurse-to-inpatient ratio; medical service and hospitalization fees; approved nurse staffing level; outpatient-to-inpatient ratio; subsidy-to-hospital-revenue ratio; and regional variation index of inpatient service expenditures. The nurse-to-inpatient ratio was associated with medical service fees reflecting patients' acuity levels and the subsidy-to-hospital-revenue ratio, but was not associated with the hospital income from hospitalization fees (the largest share of which consists of nursing fees). Public hospitals in areas with limited inpatient care resources had a higher level of approved nurse staffing and a higher subsidy-to-hospital-revenue ratio. A significant determinant of public hospitals' nurse staffing was local government-funded subsidization rather than the balance between nursing service fees and costs.