Nesfatin-1 is an anorectic protein, and we expect it to decrease during sepsis and septic shock. We aimed to analyze it and determine the relationship between Nesfatin-1 levels and quick Sequential Organ Failure Assessment(qSOFA) score, renal Sequential Organ Failure Assessment (SOFA) score, and mortality in patients with sepsis and septic shock. Sixty-nine hospitalized adult patients diagnosed with sepsis and septic shock in the internal medicine department, were included in the study after approval of the Clinical Research Ethics Committee. Sepsis diagnosis was based on the detected focus of infection, positive blood cultures, and response to antibiotics. Twenty-one healthy controls matched for age and sex with these patients were also included in the study. Sixty-nine septic patients and twenty-one healthy volunteers were included in the study. Nesfatin-1 levels were compared with covariates. Nesfatin-1 levels in septic patients were lower than that of healthy controls. There was no significant difference in Nesfatin-1 between diabetic and non-diabetic subgroups. Patients with quick Sequential Organ Failure Assessment (qSOFA) score of three had a statistically significantly lower Nesfatin-1 level than those of patients with the score of zero, one, and two. Nesfatin-1 was correlated negatively with C reactive protein. We found a statistically significant difference in 1-month mortality between Nesfatin-1 levels below and over 80pg/mL. In order to use Nesfatin-1 as a biomarker in differentiating sepsis from healthy population, more comprehensive and more studies are needed. If supported by new studies, Nesfatin-1 levels below 80 pg / mL at first admission in septic patients may direct the clinician to broad-spectrum antibiotic therapy and earlier intensive care follow-up.