The prevalence and sociomedical importance of peripheral venous diseases and peripheral venous disorders are discussed on the basis of a prospective epidemiologic field study (Basle Study) among 4529 apparently healthy workers and clerks of the Basle pharmaceutical industry. Prevalence: Pulmonary embolism was reported in 2% phlebitis in 10%. Varicose veins were present in 56% and signs of chronic venous insufficiency in 16%, respectively. Reticular and hyphen web varices predominated. Stem varicose veins were found in 15%. The sociomedical importance of varicose veins is evaluated according to the rates of complication and treatment. A medically significant varicosity was present in 12% of this working population. Three percent presented severe alterations that already had caused complications and 9% presented changes indicating.