The study aims to investigate hematological parameters of the no-reflow phenomenon (NRP) developed in patients underwent primary percutaneous coronary intervention (pPCI) due to diagnosis of ST elevation myocardial infarction (STEMI). The study sample consisted of a total of 90 patients, of which 44 patients who underwent pPCI and developed NRP without anemia and chronic renal failure (mean age was 64; 34 males and 10 females) were included in the experimental group, and the control group consisted of 46 patients with normal reperfusion flow (mean age was 58; 34 males and 12 females). In both groups, Red blood-cell Distribution Width (RDW), Mean Platelet Volume (MPV), plateletcrit (PCT), Platelet Distribution Width (PDW), and neutrophil count were observed. The demographic characteristics of both groups were similar, except the higher mean age of the experimental group (age; 64.0±12.6; 58.0±12.5). No correlation was found between development of no-reflow and incidence of risk factors such as hypertension, diabetes mellitus, dyslipidemia, smoking, family history and gender. In the no-reflow group, RDW level (16.2%±2.1; 14.2%±0.7, p<0.001), MPV level (7.9±1.2; 7.3±0.8, p<0.05), PDW level (18.1±1.2; 17.4±1.2, p<0.05), PCT level (0.2±0.06 vs 0.17±0.05) and neutrophil count (9.9±3.7; 7.1±3.3, p<0.001) was found to be higher than the control group. According to logistic regression analysis, RDW (OR; 23.4, <95% Cl 4.6-118.9, p<0.001), PDW (OR; 2.8, <95% Cl 1.2-6.4, p<0.05) and neutrophil count (OR; 1.4, Cl 1.1-1.9, p<0.05) were found to be the predictors of NRP development. Hemogram is a cheap and easy to apply test. In our study, a relationship between the NRP development and RDW, PDW, MPV, PCT, and neutrophil counts was found in patients who underwent pPCI. At the same time, RDW, PDW, and the neutrophil count were found to be predictors of no-reflow development.