In congenital factor VII deficiency the clinical picture is related to the levels of factor VII coagulant activity; when factor VII:C levels are very low the bleeding episodes can occur frequently. The most frequent bleedings are menorrhagia and metrorrhagia in females and hemarthrosis in both sexes. There are 3 immunological variants of factor VII deficiency: VII-, VIIR and VII+. Conversely, the genetic variants are 2: one characterized by no discrepancy between VII:C and VII:Ag (found in the heterozygotes of VII- and VIIR variants) and the other, in which a discrepancy between VII:C and VII:Ag is found (heterozygotes from VII+ kindreds). In factor VII deficiency, most commonly the human and ox tissue factors show the highest sensitivity to the coagulation defect, whereas the one extracted from rabbits is definitely less sensitive; the definition of functional variants is based upon a different reactivity to homologous and/or heterologous tissue thromboplastins. In no case was a PIVKA-VII-like protein found and none of the factor VII defective molecules reacted to the generation of important kallikrein activity.