To compare the technical success of antegrade uteral stent (AUS) and retrograde ureteral stent (RUS) placements in patients with malignant ureteral obstruction (MUO) and to determine the predictors of technical failure of RUS. This study retrospectively included 61 AUS placements (44 patients) performed under fluoroscopic guidance and 76 RUS placements (55 patients) performed under cystoscopic guidance in patients with MUO from January 2019 to December 2020. Technical success rates of the 2 techniques were compared using inverse probability of treatment weighting (IPTW) analysis. Logistic regression was used to identify predictive factors for technical failures. Technical success was achieved in 98.4% of the AUS group and 47.4% of the RUS group. After stabilized IPTW, the technical success rate was higher in the AUS group than in the RUS group (adjusted risk difference, 49.4%; 95% confidence interval [CI], 35.4%-63.1%). The independent predictors for technical failure of the RUS procedure were age of ≥65 years (odds ratio [OR], 5.56; 95% CI, 1.73-21.27), ureteral orifice invasion (OR, 4.21; 95% CI, 1.46-13.46), and extrinsic cancer (OR, 15.58; 95% CI, 2.92-111.81). The technical success rate of AUS placement was higher than that of RUS placement in patients with MUO. RUS failure was associated with age of ≥65 years, cancer with ureteral orifice invasion, and extrinsic ureteral obstruction.