To estimate incremental costs and healthcare resource utilization (HRU) associated with select severe adverse events (AEs) and AEs of any severity in patients with metastatic urothelial carcinoma receiving first-line (1L) therapy. Adults treated with 1L systemic therapy between January 2012 and September 2017 with ≥1 urothelial cancer diagnosis were identified using claims data. Per-patient-per-month cost differences and HRU rate ratios comparing patients with and without select AEs were estimated. Patients with any severe select AEs had higher costs than those without (cost difference = $6130 per-patient-per-month; p < 0.001). Healthcare costs and HRU for patients with select AEs were significantly higher versus those without. Select AEs during 1L therapy for metastatic urothelial carcinoma can result in significant burden to patients and healthcare systems.