Introduction Endoscopic ultrasound (EUS) is a diagnostic procedure that continues to have greater clinical applications. EUS performed before endoscopic retrograde cholangiopancreatography (ERCP) in patients with obstructive jaundice can reduce morbidity and mortality. Aim This study aimed to compare the diagnostic accuracy of both EUS and ERCP as combined or individual procedures in 30 patients diagnosed with biliary obstruction. Patients and methods From January 2017 to December 2019 in Al Azhar University Hospitals in Cairo, we recruited 30 patients with obstructive jaundice. All the patients underwent clinical examination, laboratory investigations, and abdominal US followed by EUS and ERCP procedures at the same session, and EUS findings were compared with that of ERCP. Results The diagnostic accuracy of EUS was as follows: choledocholithiasis in 92%, and malignant lesions in 95%. EUS showed pathology in 47.3% of patients who had an unknown pathology in biliary system at initial investigations. The overall diagnostic performance of EUS shows that the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 90.9, 89, 91.7, 95, and 93.5%, respectively. Regarding common bile duct stone (s), by ERCP, it was present in 13 (43.3%) cases, whereas by EUS, it was present in 12 (40%) cases. Regarding malignant lesions (ampullary tumor, cholangiocarcinoma, and pancreatic tumor), by ERCP, they were present in four (13.3%), seven (23.3%), three (10%) cases, respectively, whereas by EUS, they were present in five (16.6), six (20%), and five (16.6) cases, respectively. The complication rate was 3.3%. Conclusions EUS established high diagnostic accuracy in diagnosing the causes of obstructive jaundice, with no statistically significant difference between ERCP and EUS findings. This accurately guided ERCP need and avoided needless ERCP. EUS and ERCP in a single session for treatment of obstructive jaundice is scientifically valuable.