This case highlights a patient with Gilbert syndrome who underwent endoscopic retrograde cholangiopancreatography (ERCP) with removal of bile duct stones, who then experienced an unexplained increase in bilirubin, with total bilirubin (TBIL) levels increasing from 159.5 μmol/L to 396.2 μmol/L and to a maximum of 502.8 μmol/L after 9 d. Following the decrease in the TBIL level, enhanced magnetic resonance cholangiopancreatography (MRCP) was performed to exclude any possible remaining choledocholithiasis. Nevertheless, the serum bilirubin level increased again, with TBIL levels rising from 455.7 μmol/L to 594.8 μmol/L and a maximum level of 660.3 μmol/L with no remaining bile duct stones. A liver biopsy showed severe bile duct cholestasis with no inflammation. Based on the exclusion of other potential causes of hyperbilirubinemia and the fact that both instances of increased bilirubin occurred after ERCP and MRCP, the contrast agents iopromide and gadoterate meglumine were suspected to be the causes of the hyperbilirubinemia. As of the writing of this report, the patient\'s bilirubin levels have spontaneously returned to baseline levels. In summary, ERCP and MRCP utilizing the contrast agents iopromide and gadoterate meglumine may possibly induce prolonged hyperbilirubinemia.