Selective sampling from the main bile way using endoscopic catheterization was used in the attempt to establish parameters capable of identifying patients at risk of septic complications following endoscopic cholangiopancreatography. The results obtained evidenced a significant relationship between neoplastic type obstructions of the main bile way, age of patient and positive bile culture with increased risk of septic complications. The advisability of using local and/or systemic antibiotic prophylaxis in elderly patients with suspected neoplastic obstruction of the bile way and thus candidates for endoscopic cholangiopancreatography is considered.