Recommendations for the prevention of venous thromboembolism after major elective surgery for urologic malignancy. Venous thromboembolism is the most common preventable cause of death in cancer patients. Thromboprophylaxis has the potential to minimize morbidity and mortality. We evaluated data from the medical records of patients who underwent major urological surgery (radical nephrectomy, radical cystectomy, and pelvic exenteration) at Memorial Sloan-Kettering Cancer Center, and developed recommendations for thromboprophylaxis in this population. This analysis focused on the optimal duration of thromboprophylaxis and whether extended prophylaxis beyond 6 weeks would provide additional benefit. An interdisciplinary panel of urologic oncology physicians, oncology nurses, and hematologists/oncologists developed guidelines for prophylaxis of venous thromboembolism after major elective surgery for urologic malignancy. Of particular importance were factors to be considered in designing a comprehensive thromboprophylaxis strategy, such as patients' age, risk for bleeding, cancer diagnosis, tumor stage, and the presence of chemotherapy. We reviewed the literature and examined the cost-effectiveness of various prophylaxis strategies. Based on the evidence and the panel consensus, an algorithm for venous thromboembolism prophylaxis after major urological surgery was developed. This provides guidelines for daily practice that can be applied to patients undergoing radical nephrectomy, radical cystectomy, and pelvic exenteration. On the basis of the available data, we recommend against routine thromboprophylaxis beyond 10-14 days. At this time we cannot make a recommendation as to whether thromboprophylaxis beyond 6 weeks can provide additional benefit. The recommendations in this analysis are particularly relevant in the context of the increased utilization of novel agents, such as targeted agents (such as imatinib) and immune checkpoint inhibitors. However, future studies are needed to validate these recommendations. In addition, guidelines for prophylaxis of venous thromboembolism in patients undergoing laparoscopic radical nephrectomy and cystectomy are needed. A randomized, controlled trial is being designed by the authors to test the safety and efficacy of extending thromboprophylaxis beyond 6 weeks after major urological surgery.