OBJECTIVES: Pazopanib (PAZ) and Sunitinib (SUN) are approved as the first-line of therapy for aRCC. The purpose of this study was to compare the treatment patterns and clinical outcomes between the two therapies. METHODS: This retrospective study used US Oncology’s (USON) iKnowMed electronic health record database from Nov 2009 – Oct 2014, supplemented with chart review. Eligible patients: ≥ 18 years of age at first diagnosis of aRCC, treated with PAZ or SUN as first-line in the USON with ≥2 office visits. Propensity score (PS) matching was performed to match patients receiving PAZ to SUN. Treatment patterns, unadjusted and adjusted Cox proportional regression estimates for progression free survival (PFS) and overall survival (OS) were reported. RESULTS: A total of 153 matched pairs of PAZ and SUN patients with balanced age, gender, and Heng risk levels (p>0.05) were included. Compared with SUN, PAZ had higher relative dose intensity (RDI) (mean 0.89 vs. 0.81, p<0.01), higher compliance (99.3% vs 87.5%, p<.01), and shorter duration of treatment (mean 220.4 vs 302.1 days, p<0.05). Main reasons for discontinuation (PAZ vs SUN): disease progression (35.3% vs 37.3%, p>0.05) and toxicity (7.8% vs 19.0%, p<0.01). No significant difference was observed with PFS for PAZ (median 9.3 [95%CI, 7.6-12.1] months) compared to SUN (median 8.3 [95%CI, 6.6-10.4] months) and OS for PAZ (median 23 [95% CI, 17.7-31.9] months) compared to SUN (median 27.4 [95% CI, 16.8-40.3] months). In multivariate analysis, the adjusted hazard ratio (aHR) for PFS (aHR:0.85 [95% CI, 0.60-1.19],  p=>0.05) and OS (aHR: 0.86 [95% CI, 0.57-1.28], p>0.05)  were not significantly different in PAZ compared to SUN, respectively. CONCLUSIONS: PAZ patients had significantly higher RDI and compliance with less toxicity-related treatment discontinuation compared with SUN patients. No difference in unadjusted or adjusted PFS and OS were observed between PAZ and SUN patients.