OBJECTIVE: To review our experience with magnetic resonance imaging (MRI) in the diagnosis of deep venous thrombosis in pregnant women. METHODS: Ten gravidas with lower extremity findings suspicious for pelvic or thigh thrombosis were examined by MRI using a gradient recalled echo technique. RESULTS: In one case, MRI confirmed pelvic extension of a femoral thrombus diagnosed by Doppler ultrasound. In a second case, MRI diagnosed thrombus isolated to the pelvis. In another, MRI detected a femoral thrombus without extension into the iliac veins. Although no thrombus was detected in the remaining seven cases, pelvic vein compression by the gravid uterus was identified in five. CONCLUSION: Magnetic resonance imaging can detect deep venous thrombosis during pregnancy and should be considered when thrombosis of the pelvic veins is a clinical consideration.