Seventy nine children with typhoid fever were studied, 45 were males and 34 were females. There were 9 out of 45 males patients (20%) who had definite G-6-PD deficiency of whom 3 had acute intravascular hemolysis. The rest of the patients had transient low enzyme activity during the first few weeks of their illness, with reticulocytopenia. Their G-6-PD activities rose up to normal level later in the course of the disease while the reticulocytes were also increased. This study demonstrated that even in normal G-6-PD subjects, typhoid fever can cause transient, acquired low G-6-PD level due to bone marrow suppression. It was suggested from this study that quantitative G-6-PD assay was more useful and sensitive than the screening method and that long term follow up is needed in the case that had unexplained low G-6-PD activity.