Follow-up of patients with inferior vena cava filters was performed every 3 months with clinical controls, plain radiographs and duplex sonography. Whereas the clinical results were excellent (no recurrence of pulmonary embolism), radiological controls showed broken anchoring legs in 14 cases and a broken filter basket in one patient. In two cases, the broken anchoring prongs had perforated the inferior vena cava wall. All patients with broken filters were clinically asymptomatic. CT showed no morphological changes in these cases. As experience proves, strict follow-up of caval filters for early detection of complications is mandatory even with well-established filter types.