BACKGROUND Choledocholithiasis is the most common cause of obstructive jaundice and cholangitis and occurs in about 10% of patients with symptomatic gallstone. The aim of this study was to find preoperative and non-invasive tests for predicting common bile duct stones (CBDs). METHODS Findings of clinical examination, history, laboratory tests and ultrasound (US) in 60 patients with CBDs were compared retrospectively, with 60 patients with gallstones. The data were collected from medical charts. The sensitivity, specificity and positive predictive value (PPV) were determined. RESULTS The comparison between the two groups showed significant differences in anorexia, itching, dark urine, subicterus (slightly elevated serum bilirubin without clinical evidence of jaundice) and jaundice appearance, increased bilirubin level, aspartate aminotransferase (AST) and alanine aminotranferase (ALT), CBD diameter >6 mm and stone observation under US (P<0.05). The highest specificity (100%) and PPV (100%) were found in dark urine and pale colored stool, history of cholangitis, and icterus. Among paraclinical tests, alkaline phosphatase (ALP) had the highest specificity (72.1%) and PPV (12.5%). Under US, stone observation in CBD was the most important factor with a sensitivity of 94.5%, a specificity of 100% and a PPV of 100%. CONCLUSIONS The most important factors for predicting CBDs are history of cholangitis and pancreatitis, presence of icterus, dark urine, pale colored stool, elevation of ALP, and sonographic evidence of chledocholithiasis.