BACKGROUND: Immunological and inflammatory mechanisms have been shown to have role in both the development and progression of diabetic nephropathy (DNP). There is need for more specific markers for inflammation as the ones commonly used are influenced by many factors. Pentraxin-3 (PTX-3) seems to be a potential candidate. We aimed in our study to evaluate the changes of PTX-3 levels in different stages of DNP and its relationship with other inflammatory markers. METHODS: This is a cross sectional study in which patients with DNP at different stages were involved. Patient were divided into three groups according to estimated glomerular filtration rate (eGFR), microalbuminuria and proteinuria levels: Group-1: eGFR >60 mL/min and microalbuminuria, Group-2: eGFR >60 mL/min and macroalbuminuria, Group-3: eGFR <60 mL/min and macroalbuminuria. Besides the routine biochemical parameters, levels of PTX-3, high sensitivity C-reactive protein (hsCRP), interleukin (IL)-1 and tumor necrosis factor (TNF)-α was measured. Groups were compared with each other regarding the study parameters and correlation of PTX-3 with other markers was evaluated. RESULTS: The mean PTX-3 level in Group-2 (0.94 ± 0.26 ng/mL) and -3 (1.35 ± 1.55 ng/mL) were higher than in Group-1 (0.81 ± 0.25 ng/mL) (p = 0.009 and p = 0.012). There was a significant correlation of PTX-3 with proteinuria (r = 0.266, p = 0.016), microalbuminuria (r = 0.304, p = 0.014) and hypoalbuminemia (r = 0.197, p = 0.043). PTX-3 was not correlated with other markers of inflammation (IL-1, TNF-α and hsCRP) and diabetic metabolic parameters (hbA1c, C-peptide, insulin and HOMA-IR). PTX-3, IL-1 and TNF-α levels increased with the advancing stage of DNP while hsCRP level did not change. CONCLUSION: PTX-3 that increases similar to other markers of inflammation (IL-1, TNF-α) is a better inflammatory marker than hsCRP. Furthermore, there is a relationship between PTX-3 and proteinuria independent from eGFR.