Ultrasonic degassing attracts industrial attention as an alternative to Ar-rotary and Ar-lancing degassing, offering environmentally friendly, economical and efficient technology. This paper gives a brief historical overview of ultrasonic degassing development in the 1960s¬-2010s, discussed basic principles of cavitation-induced degassing and demonstrates various technological implementations of ultrasonic degassing technology in foundry and cast house. Batch versus continuous, gas- or vacuum-assisted versus purely ultrasonic variant of the technology are considered. Main advantages of ultrasonic degassing include rapid degassing without the use of a carrier gas, significantly reduced dross formation, absence of rotating brittle parts. There are also some technological issues associated with the ultrasonic degassing such as material selection of a sonotrode, requirement to process larger melt volumes with less ultrasonic sources, rapid re-gassing of hydrogen-depleted melt. The paper is illustrated mainly with own results.