Respiratory syncytial virus (RSV) is a leading cause of mortality in infants and young children. Despite the RSV disease burden, no vaccine is available and treatment remains non-specific. New drug candidates are needed to combat RSV. Towards this goal, we screened over 2000 compounds to identify approved drugs with novel anti-RSV activity. Cardiac glycosides, inhibitors of the membrane bound Na+/K+-ATPase, were identified to have anti-RSV activity. Cardiac glycosides diminished RSV infection in HEp-2 cells and in primary human airway epithelial cells grown at an air liquid interface. Digoxin, an FDA approved cardiac glycoside, was also able to inhibit infection of primary nasal epithelial cells with community isolates of RSV. Our results suggest that the antiviral effects of cardiac glycosides may be dependent on changes in the intracellular Na+ and K+ composition. Consistent with this mechanism, we demonstrated that the ionophoric antibiotics salinomycin, valinomycin, and monensin inhibited RSV in HEp-2 cells and primary nasal epithelial cells. Our data indicate that the K+/Na+ sensitive steps in the RSV lifecycle occur within the initial 4 hours of virus infection, but do not include virus binding/entry. Rather, our findings demonstrated a negative effect on the RSV transcription and/or replication process. Overall, this work suggests that targeting intracellular ion concentrations offers a novel antiviral strategy.