Periodontitis is a chronic immunoinflammatory disease that has been increasingly associated with systemic conditions, particularly type 2 diabetes mellitus (T2DM). Trace elements such as chromium (Cr), magnesium (Mg), and nickel (Ni) play important roles in metabolic regulation, insulin signaling, inflammatory responses, and tissue integrity. Alterations in the serum levels of these elements have been reported in T2DM; however, their relationship with periodontal status remains poorly understood. This cross-sectional observational study aims to evaluate serum Cr, Mg, and Ni levels in individuals with T2DM and chronic periodontitis and to investigate their potential associations with periodontal clinical parameters.