Isolated calf vein thrombosis in the population of patients with deep vein thrombosis is found approximately in 10 to 25 % of cases. We present 3 cases of calf vein thrombosis which occurred due to unusual causes. Specific characteristics of this form of thromboembolic disease are discussed and compared to proximal deep vein thrombosis with emphasis to symptoms, risk of complications, prognosis and therapeutic approach.