This short course gives an introduction to therapeutic use of ultrasound that is currently transitioning from research studies to clinical practice. The ultrasound induced bio-effects useful for therapy will be reviewed along with the generation of ultrasound. Mainly the absorption of ultrasound waves in soft biological tissues leading to heat creation will be described as well as the concept of the equivalent time at 43°C. The second half of the course will cover mechanical effects of ultrasound, and will discuss non-thermal therapy approaches, including lithotripsy, histotripsy, non-thermal ablation and targeted drug delivery. The potential of therapeutic methods using ultrasound currently in preclinical evaluation and clinical practice will be discussed together with the future directions and potential impact of therapeutic ultrasound. The course will emphasize technological issues and system architecture constraints, and will cover the current therapy ultrasound systems and their use in clinical practice. Examples of the results of the clinical studies will be reviewed.