The present application provides a stable, ready-to-use fosaprepitant dimeglumine formulation which is easy to administer without need of any reconstitution step and has a desirable solubility, stability and safety profile. The concentration of the fosaprepitant dimeglumine in the liquid formulation is preferably less than about 80 mg/ml, or more preferably between about 20 mg/ml to about 60 mg/ml. In certain embodiments, the liquid formulation retains at least about 90% chemical stability of the fosaprepitant dimeglumine after storage for a commercially reasonable amount of time at a temperature between about 0° C. to about 40° C.