The paper presents results of studies demonstrating a significant impact of double transducer probe characteristics on the interpretation of discontinuity types in the ultrasonic quality control of forgings. Double transducer probes are characterised by significant differences in the width of an ultrasonic beam in two mutually perpendicular directions, i.e. perpendicular and parallel to the plane of the separation of probes. These circumstances may lead to the misinterpretation of discontinuities types (point-like/extensive) and thus, to the adoption of inappropriate criteria for the evaluation of indications and, eventually, to the determination of improper sizes of discontinuities mistakenly interpreted as extensive. This article is addressed to NDT personnel performing ultrasonic tests using double transducer probes as well as to those participating in courses preparing for examination according to ISO 9712 in the product sector of forgings.