Treatment with fosfomycin alone and associated to subtherapeutic doses of chloramphenicol or of ampicillin, has been tried on 50 patients with typhoid fever and on four carriers of S. typhi in the Hospital del Rey. 15 patients were treated with fosfomycin alone, 22 with fosfomycin plus chloramphenicol and 13 with fosfomycin plus ampicillin. The treatment lasted 15–20 days. The results have been evaluated clinically and bacteriologically, haemo- and coprocultures being carried out. The sensitivity of the isolated germs has been studied, including MIC and the synergism in vitro between fosfomycin-chloramphenicol and fosfomycin-am-picillin. Fosfomycin, chloramphenicol and ampicillin determinations have been carried out on the blood. The cures obtained were 67, 82 and 92% respectively with fosfomycin, fosfomycin-chloramphenicol and fosfomycin-ampicillin. We believe that this antibiotic can be useful in the treatment of typhoid fever, associating it to chloramphenicol or ampicillin, due to the synergism existing between them and given the results we have obtaine