Purpose: Gestational diabetes mellitus (GDM) is defined as glucose intolerance with first onset or diagnosis in pregnancy. This study evaluated clinical and biochemical parameters in a possible association between GDM and gingival inflammation. Materials and Methods: A total of 87 pregnant women - 44 with GDM and 43 without (NGDM) - were included. Subgroups were created according to gingival inflammation. Plaque index (PI), bleeding on probing (BOP), and probing depth (PD) were recorded. Results: Age, anthropometric variables and baby weight (g) were all statistically significantly higher in the GDM group (p 0.0001). Systolic and diastolic blood pressure (mmHg), saliva, serum leptin and adiponectin levels were similar in the GDM and NGDM groups (p = 0.605, p = 0.662, p = 0.737, and p = 0.596, respectively). Salivary adiponectin levels were statistically significantly higher in the two subgroups with gingivitis compared to those with clinically healthy periodontium (p 0.01). Serum adiponectin levels were statistically significantly higher in the NGDM subgroup with gingivitis than the NGDM group with clinically healthy periodontium (p 0.05). Statistically significant positive correlations were found between PD, PI, BOP and saliva adiponectin levels in the GDM group (p 0.05). Positive correlations were also found between clinical periodontal parameters and saliva, serum levels of adiponectin in the control group without GDM (p 0.05). Conclusion: The higher salivary adiponectin levels in the gingivitis groups suggest that gingival inflammation is more likely to influence local inflammatory parameters both in the presence and absence of GDM. Further larger-scale studies are required to better clarify the possible interactions between gingival inflammation and GDM. Keywords: adiponectin, gestational diabetes, gingivitis, MeSH, leptin, saliva