The study comprised 36 patients who were divided into two groups. In the first one, there were acute or chronic infectious diseases and the second was a control group. In all of them, the following laboratory counts were done: hemoglobin, hematocrit, leukocyte; also, measurement of protein electrophoresis, of serum iron and of total fixation capacity of iron (transferrin). The procedure was that of a blind study, so that the laboratories responsible for the measurements were not given any clinical information on the different patients. Hypochromic anemia of different degrees of severeness was reported in all infected patients and was attributted to nutritional and infectious factors. In spite of decreased levels of hemoglobin and iron, it was shown that transferrin did not rise, but otherwise, dropped in these patients; therefore, the capacity to convey and fix iron is decreased. This would be a fact resulting in a greater susceptibility, to suffer infections, as has been confirmed in previous studies. A close relationship was found at pediatric level among hypochromic anemia, drop in transferrin levels, poor nutrition and increase of infectious diseases.