Evaluation was made of the clinical-bacteriological results of treatment with fosfomycin on a group of 27 patients with infectious respiratory pathology. The group is made up of patients with respiratory infections diagnosed as pneumonias, bronchopneumonias, acute bronchitis and chronic bronchopneumopathies. The dosis of fosfomycin used varied between 4 and 12 g/day, administered during a period of 1 or 2 weeks. The results of the treatment expressed in clinical and bacterio-logcal parameters have been successful in 15 and 21 cases for their bacteriological response and their clinical response respectively.