Cytologic brushings of ductal lesions noted at ERCP are a reliable method of diagnosing malignancy. However, prior studies have involved only small numbers of patients. This study presents the results of attempted brushings in 69 patients. A satisfactory specimen was obtained in 62 patients (90%). The overall sensitivity was 44% with 100% specificity. Common bile duct brushings had a higher sensitivity rate than did pancreatic brushings. Similarly, biliary tract cancer was more likely to be diagnosed than was pancreatic cancer by brushing. Markedly atypical cells were identified in 36% of patients with a false negative cytology result. These findings were not seen in patients with benign disease. Two patients developed mild pancreatitis and one developed cholangitis. It is unclear what role the act of brushing had on causing these complications.