<b>Purpose</b><br/>This study aimed to evaluate the clinical efficacy and patency of stents placed for symptomatic iliac vein or IVC obstruction caused by malignant tumors. Material and Methods: A total of 34 consecutive patients with malignant iliac vein or IVC obstruction underwent stent placement. We reviewed their electronic medical records, pre- and post-procedural CT scans, and angiograms retrospectively, and evaluated technical success, clinical success, and patient-based and vessel-based reocclusion rates confirmed by follow-up cross-sectional images. The reocclusion rate difference between IVC and iliac stents was also assessed. <br/><b>Results</b><br/>All patients complained of leg and/or trunk edema. The stents were placed in the following locations: IVC (n = 9); iliac veins (n = 19); and both IVC and iliac veins (n = 6). Technical success rate was 100% and the clinical success rate was 87.5% during hospitalization. Cross-sectional area of the affected thigh was significantly decreased after stent placement (mean 11.7%, p = 0.003). The median follow-up period was 65 days (Q1–Q3, 28.5–227.3; IQR, 198.8). The patient-based reocclusion rate was 42.8%. The vessel-based reocclusion rates for IVC (12.5%) tended to be lower than those of iliac veins (45%), though the difference was not statistically significant (p = 0.194). <br/><b>Conclusion</b><br/>Stent insertion for iliac vein or IVC obstruction secondary to malignancy is technically feasible and can help to improve patients’ symptoms. IVC stents tend to achieve a higher rate of patency than iliac vein stents.