Abstract Objective To investigate the role of CD40 ligand and P-selectin in the mechanism of decreased incidence of cardiovascular disease in Gilbert's syndrome (GS). Design and methods The soluble forms of CD40 ligand (sCD40L) and P-selectin (sP-selectin), and high sensitive C reactive protein (hs-CRP) levels were investigated in subjects with GS ( n = 25) and compared to healthy controls ( n = 53). Results sCD40L and hs-CRP levels were significantly lower in GS compared to the controls (0.33 ± 0.27 vs 0.71 ± 0.37 ng/mL, p < 0.001 and 0.51 ± 0.45 vs 1.16 ± 1.31 mg/L, p = 0.046, respectively). Both sCD40L and hs-CRP were negatively correlated with total bilirubin ( r = − 0.5, p < 0.001 and r = − 0.34, p = 0.002, respectively). sP-selectin levels were lower in GS when compared to the controls but the difference did not reach statistical significance ( p = 0.052). No correlation was found between the plasma levels of sCD40L, sP-selectin and hs-CRP. Conclusion These novel findings suggest that reduced sCD40L and hs-CRP concentrations may have a role in the mechanism of protection against atherosclerosis in GS.