e16020 Background: Advanced urothelial carcinoma (UC) patients have a poor prognosis. In the first and second line UC treatment setting, we investigated real world outcomes and evaluated the prognostic role of the neutrophil to lymphocyte ratio (NLR). Methods: A retrospective analysis was performed on advanced UC patients treated with systemic therapy. Overall response rates (ORR), time to treatment failure (TTF) and overall survival (OS) were calculated. Cox regression analysis was performed to examine the association between baseline NLR (low NLR<3 vs high NLR≥3) and TTF and OS. Results: We evaluated 233 advanced UC patients. In the first line setting, the ORR was 25%. Median TTF and OS were 6.9 mo and 9 mo, respectively. Low baseline NLR was significantly associated with improved 8.3 mo median TTF, versus 5.8 mo for high NLR patients (p=0.05). Low NLR was significantly correlated with a longer median OS of 13.1 mo, in comparison to 8.2 mo in patients with high NLR (p=0.007). In the second line, an ORR of 22%, a median TTF of 4.1 mo and a median OS of 8 mo were observed. Low NLR in the second line was significantly associated with improved median TTF at 7.9 mo, versus 3.6 mo for patients with high NLR (p=0.03). Second line low NLR was also significantly associated with a longer median OS of 12.2 mo, in comparison to 6.8 mo in patients with high NLR (p=0.003). Conclusions: In this real world analysis of advanced UC patients, first line outcomes were lower than expected, while response rates in the second line compared favorably to the literature, suggesting a highly selected patient population actually receives second line treatment. A low baseline NLR in the first and second line is associated with improved TTF and OS and warrants further prospective evaluation. [Table: see text]