Background: Patients with upper tract urothelial carcinoma (UTUC) can be managed with either radical nephroureterectomy (RNU) or kidney sparing surgery (KSS) depending on the pathology and patient specific characteristics. Due to the rarity of this disease, high-level evidence is lacking with regard to clinical and oncologic outcomes after surgery. This study aims to compare outcomes of RNU with KSS for patients with high-grade (HG) UTUC. Methods: We retrospectively reviewed patients with >1 year follow-up who were treated for HG UTUC at our institution from 2015-2021. Oncologic and clinical outcomes were recorded. Procedure-related burdens, including total number of procedures under anesthesia, anesthesia time, and days hospitalized were collected. Results: 65 patients were analyzed, with 46 patients treated via RNU and 19 treated via KSS. There were no differences in the ASA or CCI between patients in the two groups. The 5-year overall survival (OS) was 65.2% (95% CI, 52.8%-80.5%) for RNU and 44.4% (95% CI, 26.5%-74.5%) for KSS. The 3-year metastasis-free survival was 78.3% for RNU and 78.9% for KSS. The 3-year recurrence-free survival, including recurrences in the bladder, was 47.8% (95% CI, 35.4%-64.7%) for RNU and 43.8% (95% CI, 25.1%-76.3%) for KSS. A decline of GFR <10 2 years after surgery occurred in 97.1% of patients treated with RNU and 100.0% of those treated with KSS. The total number of procedures under anesthesia was higher for KSS than RNU at 3.4 +/- 1.7 vs 2.1 +/- 1.7, respectively (p = 0.0155). The total number of TURBTs for KSS and RNU was similar at 0.6 +/- 0.7 vs 1.1 +/- 1.7, respectively (p = 0.9538). The total number of days hospitalized for KSS was similar to RNU at 5.5 +/- 4.3 vs 6.8 +/- 4.6, respectively (p = 0.3579). The total anesthesia time for KSS was 400 +/- 218 min and was 474 +/- 185 min for RNU (p = 0.2561). Conclusions: There were similar oncologic and clinical outcomes in patients with HG UTUC treated with either KSS or RNU. Patients treated with KSS saw a higher procedural load. There was a trend towards lower OS for patients treated with KSS but this was not statistically significant, likely due to the small sample size. Larger datasets are needed to further evaluate outcome and treatment burdens of RNU vs KSS as treatment options for patients with HG UTUC.