Ultrasound is a non-conventional processing technology that can be used both to food preservation and the improvement of physical properties. The objective of this work was to study the effects of sonication on guava juice quality through selected physical properties, such as colour, serum cloudiness, pulp sedimentation and microstructure through optical microscopy. For this, guava juice containing 15% of pulp was processed using the ultrasound technology (121 W/L of volumetric power and 20 kHz of frequency, 1.26 cm2 titanium tip) up to 9 minutes at 25ºC. The evaluation was carried out during 14 days of storage at 25ºC. The juice microstructure showed the rupture of guava cells, releasing the intracellular content (carotenoids) to the serum. It can indicate a possible higher absorption of this component than when it is enclosed in the guava cells (unprocessed juice). The ultrasound processing did not show significant changes in the instrumental colour. The serum cloudiness increased with the sonication time, due to the decrease in the particle size of guava cells. The reduction on the guava particles promoted a higher stability to the juice. The juice processed for 9 minutes using the ultrasound technology showed no sedimentation even after 14 days of storage – while the control juice started to precipitate in the first hour of storage. Therefore, the application of ultrasound processing showed enhancement on physical proprieties and stability of guava juice. Consequently, the results indicated that the ultrasound technology can be used in substitution of the hydrocolloids addition for guarantee physical stability on guava juice.