Technical problems encountered during percutaneous placement of 165 Bird's Nest filters over 16 months are described. Filter deployment was successful in all patients. Although frequent, the technical problems were all minor with no long-term sequelae. Several problems were inherent to the design of the filter. Other problems related to the patient's anatomy were seen as well. Because deployment of the Bird's Nest filter is more operator-dependent than is deployment of other types of inferior vena cava filters, knowledge of pitfalls and means to avoid problems are particularly important.