Background: Few data are available concerning the prognostic and predictive role of CGA in elderly pts ≥70 years with metastatic RCC treated with either Sun or Paz. Materials and Methods: We retrospectively reviewed the charts of all elderly pts with advanced RCC treated at our Institute with either Sun or Paz, with at least 6 months follow-up after starting treatment. Every pt received at baseline a CGA and was classified as fit, vulnerable or frail according to Balducci’s Criteria. Results: We identified 73 pts who started therapy from January 2006 to March 2018, median age 76 years (range 70-89), 63% males; 42.5% fit and 57.5% unfit pts (38.3% vulnerable, 19.2% frail). Sun to Paz ratio was 40 to 33 pts with a median duration of treatment of 10.8 months; incidence of G1/2 toxicities was 85% vs 93.9% (p = 0.28), G3/4 was 37.5% vs 30.3% (p = 0.63), dose reduction was necessary in 77.5% vs 78.8% of pts (p = 0.9), respectively. Median PFS and OS with Sun or Paz were 13.6 vs 9.4 months (p = 0.152) and 27 vs 22.3 months (p = 0.641), respectively. CGA fit category predicted longer PFS (p = 0.039) and OS (p = 0.001) in the whole cohort. We found no significant differences between fit and unfit pts according to incidence of G1/2 adverse events, incidence of dose reduction or necessity to early suspend treatment due to toxicity, while the incidence of G3/4 events was lower in the fit subgroup (p = 0.026). Out of 67 pts progressing after first line therapy, 27 (40.3%) received a second line consisting in Nivolumab (22.4%), Everolimus (13.4%) and Sorafenib (4.5%), while 40 (59.7%) received only palliative treatments. CGA fit category significantly correlated with a higher chance of receiving a second line treatment (p = 0.004). Conclusions: In our retrospective single-center experience, CGA has a strong prognostic value in terms of OS and has the ability to discriminate pts at higher risk of experiencing G3/4 toxicities with Sun or Paz, with shorter PFS and lower chance of receiving a second line treatment. There were no striking differences in terms of toxicity rates between Sun or Paz, although different in type and possibly biased by patient selection.