An outbreak of Typhoid fever (TF) occurred in Gharbeya Governorate in Egypt during November and December 1990. Ninety children with mean age of 9.64 +/- 3.67 years and 43 adults with mean age 22.51 +/- 5.36 years were treated in Tanta fever hospital (TFH) during this outbreak. Resistance of TF during the outbreak to the usual antibiotics given in TFH was the main feature of the outbreak, including resistance to chloramphenicol, co-trimoxazole, ampicillin, tetracycline, and gentamycin. Such resistance was detected in vitro as well as in vivo. Sensitivity was present in vitro and in vivo to ofloxacin (OF) and cefotaxime. The clinical response of OF was 96 per cent in children and 82 per cent in adults. No significant difference in side effects was detected in children treated with OF and those treated with other drugs after 6 months follow up.