Chronic inflammation underlies the bidirectional relationship between diabetes and periodontitis, a process that may be further exacerbated in the presence of diabetic nephropathy. While the roles of inflammatory cytokines such as TNF-α and IL-10 in both periodontal tissue destruction and diabetes-related microvascular complications remain unclear, NGAL is recognized as a biomarker for diabetic nephropathy but its association with periodontal disease is not well established. This study aimed to comparatively evaluate salivary and serum levels of NGAL, TNF-α, and IL-10 according to different periodontal conditions in individuals with newly diagnosed diabetes and those with diabetic nephropathy.