Data on Medicare discharges (n = 4086) in the discharge sample of the National Nursing Home Survey were used to study the association of registered nurse (RN) and physical therapist (PT) staffing levels to the outcomes and length of Medicare nursing home stays. Marginal effects were calculated in multinomial logistic modeling of Medicare beneficiaries who recovered/stabilized, died, or were hospitalized. Linear regression models on length of stay (LOS) were constructed. Higher RN staffing was related to fewer hospitalizations whereas greater PT staffing was associated with more recovered/stabilized outcomes and fewer deaths. RN and PT staffing may play different, though complementary, clinical roles affecting outcomes. Higher RN and PT staffing levels also reduced LOS of recovered/stabilized outcomes. The staffing increases involved in reducing LOS and hospitalizations appear substantial. Research on best practices that can amplify effects of nursing home staffing increases on quality seem to be the next step to further quality improvement. (Am J Med Qual 2008;23:465-474)