Aim: Levels of Serum Procalcitonin (PCT), C-Reactive Protein (CRP), Leukocyte (WBC) and Mean Platelet Volume (MPV) were evaluated in sepsis patients. We evaluated the diagnostic accuracy of different inflammatory markers to discriminate sepsis caused by different pathogens. Material and Method: In this study we included 126 episodes of bacteremia from 126 patients with sepsis. Medical records of patients who had bacteremia caused by Gram-negative bacteria (GN), Gram-positive bacteria (GP) or yeast were reviewed, and information about PCT and other inflammatory markers was recorded. Mann-Whitney U test and Spearman's correlation analysis were used for statistical analysis. Results: 60.4% of the cases (n=76) were GN, 31.7% (n=40) were GP and 7.9% (n=10) were yeast. There was a statistically significant difference between PCT, CRP, and MPV levels according to the microorganism (p=0.001, p<0.01). There was no statistically significant difference between WBC measurements according to the microorganism (p>0.05). Discussion: According to the microorganism, gram positivity cutoff points were determined for PCT as (≤12.17), CRP as (≤9.70) and MPV as (≤9.32). In bilateral comparisons, there was a significant increase in GN and yeast sepsis, while a significantly low level was found in GP sepsis. There was no significant difference between GN and yeast. When the measurements of PCT according to bacterial species are examined, the highest measurement was 44.6 ng/ml with Escherichia coli bacteria, followed by Candida bacteria with 12.6 ng/ml.