The present invention provides an inhaled dry powder formulation containing a combination of fosfomycin salt and tobramycin-leucine compound particles. The use of such formulation for the treatment of patients who have Chronic Obstructive Pulmonary Disease (COPD) and who are experiencing or at risk of experiencing acute exacerbation, as well as patients who have other bacterial infections of the respiratory tract, particularly the lower respiratory tract, and methods for treating the same are also provided.