Ultrasound is a portable and cost effective method of medical imaging, thus enabling its use in developing countries as well as those more technologically advanced. Many researchers are pursuing alternate therapeutic uses for ultrasound to take advantage of these qualities, one of which is studied here. Lipid vesicles coupled with ultrasound are evaluated as a possible targeted, triggered, drug delivery pathway, using ultrasound as both the target tracking and release mechanism. Ultrasound can cause gas bubbles in solution to oscillate in size or collapse in response to the oscillatory pressure waves. The forces resulting from these mechanical responses are capable of releasing the internal contents of a lipid vesicle. It is necessary to understand the interactions between these lipid bilayers and ultrasonic pressure waves in order to design vesicles that will react favorably to the forces applied to them. The aim of the present study was to determine the effect of vesicle composition on ultrasound induced leakage. A self-quenching fluorescent dye was encapsulated in lipid vesicles of DOPC-DPPC-Cholesterol and DMPC-Cholesterol, with varying mole fractions of cholesterol. The samples were exposed to 20 kHz ultrasound via a probe tip transducer in small time intervals with significant rest time between each interval (to prevent temperature effects). Steady-state fluorescence spectroscopy was used to quantify the dye leakage as a result of each exposure to ultrasound, and a leakage profile for each vesicle composition was obtained. It was found that changes in cholesterol content caused distinct changes in the release profile, and that these trends can be interpreted in terms of lipid phase behavior.