BACKGROUND: The platelet!lymphocyte ratio (PLR) and neutrophil/lymphocyte ratio (NLR) are associated with inflammation and atherosclerosis. Our aim is to investigate the relationship between ST segment resolution and these inflammation markers in patients with ST segment elevation myocardial infarction (STEMI) following thrombolytic treatment. METHODS: We included 55 patients suffering from STEMI who were administered thrombolytic treatment and met the inclusion criteria. The sum of ST segment elevation was measured at presentation and 60-90 minutes after administration of the thrombolytic agent. According to the sum of STR, patients were divided into two groups (patients with STR >50% vs. those with STR <= 50%). RESULTS: In this study, 58.2% (N.=32) and 41.8% (N.=23) of patients were found to have STR>50% and STR <= 50%, respectively. Time to treatment was significantly higher in the STR <= 50% group than in the STR>50% group (3.3 +/- 2.78 1.99 +/- 1.4 h, P=0.024). There was no statistically significant association between STR and neutrophil, lymphocyte, platelet white blood cell count, mean platelet volume, plateletcrit, hemoglobin, serum glucose and urea. NLR was significantly higher in the STR <= 50% group than in the STR>50% group (4.511:3.24 vs. 3.91 +/- 6.50, P.044). The PLR was also significantly higher in the STR <= 50% group (140:t 79 vs. 102 +/- 69. P=0.030). CONCLUSIONS: Admission PLR and NLR might be valuable in the prediction of impaired ST segment resolution following thrombolysis in patients with STEMI.