The distribution of Tf phenotypes in the population of Padua was investigated by ultrathin-layer isoelectric focusing. In our sample (n = 618) nine phenotypes, Tf C1, C2, C3, C3-1, C2-1, C3-2, C1B, C2B and C1D, were observed and the following frequencies calculated: TfC1 = 0.77837; TfC2 = 0.1804; TfC3 = 0.03641; TfB = 0.0040; TfD = 0.0008. These gene frequencies have been compared to those found in other populations. Analysis of 101 mother-child pairs was in agreement with an autosomal codominant mode of inheritance.