Factor VII (FVII) plays a critical role in the initiation of blood coagulation, and patients with dysfunctional or reduced levels of this protein are susceptible to mucosal bleeding. There is poor correlation between the clinical presentation and the phenotypic data; and in cases of a mild bleeding tendency, mild to moderate reductions in both FVII antigen and activity may be overlooked. The prevalence of FVII deficiency may therefore be underestimated. Polymorphic differences throughout the FVII gene are associated with variations in plasma FVII antigen and activity levels. This study highlights the significance of mild FVII deficiency, and examines the importance of seven previously published polymorphisms in such patients.