Ultrasonography is the most widespread imaging technique used in the diagnostics of the pathologies concerning the organs in the abdominal cavity. Similarly to other diagnostic tools, errors may occur in ultrasound examinations. They generally result from inappropriate techniques, which do not conform to current standards, or erroneous interpretation of obtained images. A significant portion of mistakes is caused by inappropriate quality of the apparatus, the presence of sonographic imaging artifacts, unfavorable anatomic variants or improper preparation of the patient for the examination. This article focuses on the examiner-related errors. They concern the evaluation of the liver size, echostructure and arterial and venous vascularization as well as inappropriate interpretation of the liver anatomic variants and the vascular and ductal structures localized inside of it. Furthermore, the article presents typical mistakes made during the diagnosis of the most common gallbladder and bile duct diseases. It also includes helpful data concerning differential diagnostics of the described pathologies of the liver, gallbladder and bile ducts. The article indicates the most frequent sources of mistakes as well as false negative and false positive examples which result from these errors. What is more, the norms used in the liver, gallbladder and bile duct evaluations are presented as well as some helpful guidelines referring to the exam techniques and image interpretation, which allows for reducing the error-making risk. The article has been prepared on the basis of the report published in 2005 by the Polish experts in the field of ultrasonography and extended with the latest findings obtained from the pertinent literature.