An increased pretreatment neutrophil-lymphocyte ratio (NLR) is associated with poor prognosis in colorectal, gastric, and ovarian cancer; malignant mesothelioma; and renal cell carcinoma. The present study aims to define the predictive value of preoperative peripheral blood count NLR in non-muscle-invasive bladder cancer (NMIBC) and muscle-invasive disease (MIBC) patients. There were in total 291 patients, 241 males and 50 females. Out of these, 156 male and 36 female patients were in the NMIBC group and 85 male and 14 female patients in the MIBC group. In the NMIBC group, 172 patients had low-grade and 20 high-grade papillary urothelial carcinoma. The mean age of the patients in the NMIBC group was 64±13, ranging from 27 to 97. The mean age of the patients in MIBC group was 70.5±10, ranging from 27 to 95. A statistically significant relation between patient ages and tumor invasiveness was determined (p=0.023, 95 % confidence interval (CI) 63.3-66.7). The mean tumor size of the NMIBC group was 2.1±1.09 (cm) (range 0.5-8), and of MIBC group 3.6±1.5 (cm) (range 0.8-9). There was a statistically significant relation between the tumor size and invasiveness (p=0.002, 95 % CI 2.8-4.4). In the NIMBC group, 149 (77.6 %) of them have NLR≤2.5 and 43 (22.4 %) have NLR>2.5. Also, in MIBC, 67 (67.7 %) of them have NLR≤2.5 and 32 (32.3 %) have NLR>2.5. The mean NLR in the NMIBC group was 2.4±0.1 (range 0.08-6.49, 95 % CI 1.52-2.71) and in the MIBC 2.9±0.2 (range 0.08-16.72, 95 % CI 1.67-2.97). In terms of NLR, there was a statistically significant difference between the NMIBC and MIBC groups (p=0.028). Platelet-lymphocyte ratio (PLR) of the two groups was also analyzed. The PLR of the NMIBC group was 12.8±15.1 (range 3.38-19.1) and of the MIBC 13.6±8.78 (range 0.18-63), yet there was not any statistically significant difference (p=0.810, 95 % CI 11.4-14.8) (Table 1). The correlation tests revealed a positive correlation between the age (r=0.144, p=0.024), tumor size (r=0.193, p=0.02), and tumor invasiveness NLR (r=0.138, p=0.031). NLR can be used to determine tumor invasiveness as a cost-effective, common, and simple biomarker in bladder cancer (BC). © 2014 International Society of Oncology and BioMarkers (ISOBM).