This study reviews our experience in the management of deep vein thrombosis (DVT) of the lower extremity during pregnancy and analyzes the outcome of various treatment alternatives, including conventional full-dose heparin therapy and Greenfield filter insertion. Twenty-four patients treated over an 8-year period were reviewed. Fifteen patients were treated with conventional full-dose intravenous heparin therapy for 5 to 10 days, followed by subcutaneous low-dose heparin until labor, and continued for 6 weeks postpartum (Group A); Eleven patients had Greenfield filters inserted, followed by the same low-dose subcutaneous heparin regimen (Group B). There were 18 femoral or iliofemoral, 5 femoropopliteal, and 1 popliteal and below-knee DVT. The indications for Greenfield filter insertion included two patients in Group A (one with pulmonary embolism, despite adequate heparin therapy, and one with significant bleeding). Nine other patients had prophylactic indications: two for free-floating iliofemoral DVT, three with iliofemoral DVT (occurring just 1-2 weeks before labor), and four with femoropopliteal DVT. There were three immediate major complications (pulmonary embolism, bleeding, or death) in Group A; two with pulmonary embolism, one of which was fatal, and one with significant bleeding (3 of 15 patients; 20%). No major complications occurred in Group B. On long-term follow-up (mean, 61 months), 4 of 12 patients (33%) in Group A had significant leg swelling, with partial resolution of DVT in 2 patients and venous occlusion in 2 patients by duplex ultrasound. This is in contrast to 3 of 11 patients (27%) in Group B with significant leg swelling. There was no fetal morbidity or mortality in either group. Conventional full-dose heparin therapy for DVT of the lower extremity in pregnancy can carry significant morbidity and mortality. Greenfield filters may be used safely in some of these patients.