Objective It is known that chronic inflammation plays an important role in the etiopathogenesis of biliary tract carcinoma (BTC). In this study, we wanted to examine the effect of neutrophil-to-lymphocyte ratio (NLR), derived neutrophil-to-lymphocyte ratio (dNLR), and prognostic nutritional index (PNI) on survival in advanced BTC treated with gemcitabine plus cisplatin (GEMCIS) regimen. Methods Forty-two patients with advanced BTC treated with GEMCIS regimen were included in the study. Measurements for NLR, dNLR and PNI were calculated with available formulas. NLR, dNLR, and PNI values were dichotomized based on receiver operating characteristic curve analysis (cut-off values 3.94, 2.66, and 46, respectively). Univariate and multivariate analyses were performed to identify prognostic factors for 6-month progression free survival (PFS) and overall survival (OS) using a Cox proportional hazards model. Results The mean PFS was 5.3 (median 5) months, and the mean OS was 10.7 (median 11) months. The pre-treatment increased NLR (>= 3.94) value was prognostic for lower 6-month PFS and 12-month OS rates. dNLR was not found to be important for survival times. Low PNI (< 36) value was prognostic for lower 6-month PFS and 12-month OS rates. In the multivariate analysis, increased NLR value was determined as an independent prognostic factor for 6-month PFS. Conclusion In patients with advanced BTC using GEMCIS as the first-line chemotherapy regimen, NLR and PNI can be used as prognostic inflammatory markers for 6-month PFS and 12-month OS.