Aim:In this study, it was aimed to compare serum periostin levels of patients with and without bone marrow fibrosis among newly diagnosed multiple miyeloma (MM) patients.Materials and Methods:Thirty patients who were diagnosed with fibrosis in bone marrow biopsy from 36 MM patients over the age of 18 who were newly diagnosed in our center in line with the recommendations of national and international guidelines and were selected for serum periostin levels were included in the study. The patients were divided into two groups as those with and without fibrosis.Results:While the serum periostin level of the patients with bone marrow fibrosis was 29.22 ng/mL, the serum periostin level of the patients without fibrosis was 17.97 ng/mL, which was statistically significantly higher (p