Aim Adiponectin is an adipocyte-secreted protein associated with insulin sensitivity. T-cadherin is a receptor for high and medium molecular weight adiponectin. In GWAS, T-cadherin gene (CDH13) polymorphisms are associated with circulating adiponectin levels. This study investigated the associations between genetic variants of CDH13 and type 2 diabetes (T2D), and its related parameters, in a Caucasian population. Methods Two polymorphisms of CDH13 (rs11646213 and rs3865188) were genotyped in two French cohorts, a general population from the D.E.S.I.R. study (n = 5212) and people with T2D in the DIABHYCAR study (n = 3123). Baseline adiponectin levels were measured in D.E.S.I.R. participants who were normoglycaemic at baseline, but hyperglycaemic after 3 years (n = 230), and in controls who remained normoglycaemic (n = 226) throughout. Results In a cross-sectional analysis, CDH13 genotype distributions differed between those with and without T2D, with T2D odds ratios (OR) of 1.11 (95% CI: 1.04–1.18; P = 0.001) and 0.92 (95% CI: 0.87–0.98; P = 0.01) for rs11646213 and rs3865188, respectively. The rs11646213 variant, associated with a higher OR for T2D, was also associated with higher BMI (P = 0.03) and HbA1c (P = 0.006), and lower plasma adiponectin levels (P = 0.03) in the D.E.S.I.R. participants. Conversely, the rs3865188 variant, associated with a lower OR for T2D, was also associated with lower BMI (P = 0.03), HbA1c (P = 0.02) and Fatty Liver Index (FLI; P ≤ 0.01), and higher plasma adiponectin levels (P = 0.002). Associations with HbA1c, FLI and adiponectin levels persisted after adjusting for BMI. Conclusion CDH13 polymorphisms are associated with prevalent T2D in this French population study. The association may be mediated through effects on BMI and/or plasma adiponectin.