This document specifies requirements and methods for periodic testing of the quality of diagnostic medical ultrasound systems with linear array, curved linear array, single element, annular array, phased array, matrix linear array transducers and two-dimensional arrays. Image interpretation and measurement workstations are included. Usually, “periodic testing?? is referred to here as “quality control??. This document represents a minimum set of such tests intended for frequent users of medical ultrasound systems, for quality control professionals in their organization, or those hired from other quality-control and/or service-provider organizations. System-manufacturing and repair companies might well employ other or additional tests. The tests are defined in three levels, with the simplest and most cost-effective performed most frequently, similarly to [1]. More complete tests for acceptance testing and for assessment at times of particular importance or concern are specified in IEC61391‑1 , IEC61391‑2 and IECTS62791 [15]. These more complete tests are categorized as performance evaluation, rather than quality control or frequent periodic testing. This document also defines terms and specifies methods for measuring (for quality maintenance or quality control) the maximum relative depth of penetration of real-time ultrasound B-MODE scanners, though this penetration measure is listed as less frequently applied. Frequent distance-measurement accuracy tests are recommended only for certain classes of position encoding that are not now known to be highly stable and without bias. The types of transducers used with these scanners include: mechanical probes; electronic phased arrays; linear arrays; curved arrays; two-dimensional arrays; three-dimensional scanning probes based on a combination of the above types. Transducers not readily amenable to transducer-element testing by the simple image-uniformity procedures specified (for example, phased array and 2D-array transducers) are tested only partially by maximum relative depth of penetration. System manufacturers are encouraged to provide pulsing patterns of the transducer elements to allow testing of individual elements or small-enough groups of elements to enable users to detect significant element failure or to provide access to another implemented and explained element-test program. Dedicated Doppler systems are excluded from coverage here as specialized equipment is required to test them. This test equipment can be specific to the intended application of the Doppler system. All scanners considered include basic pulse-echo techniques. The failures to be detected by the recommended pulse-echo tests also will affect the operation of other modes, such as colour-flow, harmonic-, elasticity- and compound imaging. The test methodology is applicable for transducers operating in the 1MHz to 17MHz frequency range and could be made applicable up to 40MHz, if the depth of penetration were allowed to be relative, rather than absolute, and phantom stability were verified [15]. Image-uniformity QC is applicable to transducers operating in the 1MHz to 40MHz frequency range as the requirements for phantoms are not stringent. NOTE Phantom manufacturers are encouraged to extend the frequency range to which phantoms are specified to enable relative depth-of-penetration tests of systems operating at fundamental and harmonic frequencies above 17MHz.