The ultrasound (US) technology is an emerging technology that can be used to control microbial spoilage or to promote desirable changes in liquid foods through the effect of acoustic cavitation. Guava is a tropical fruit which is related to healthy benefits due its consumption. Changing the rheological parameters of juices can be useful for process design, sensory quality and consume acceptance. This work evaluated the effect of US Technology on the steady-state shear rheological properties and microstructure of guava juice. Samples were processed by US at 5000 W/L during 30 minutes at 25ºC. The rheological evaluation was carried out using a stress-controlled rheometer, using a cross-hatched parallel plates geometry with gap of 1000 µm. The rheological evaluation was carried out at 25ºC, considering a pre-shearing step at 300 s-1 during 10 minutes, to evaluate the thixotropy, followed by a linear decreasing stepped protocol (300 to 0.1 s-1) in order to guarantee the steady-state condition. The US increased the juice thixotropy, whose rheological behaviour was described by the Figoni-Shoemaker model. The initial stress value increased from 7.6 to 16.1 Pa, the equilibrium stress increased from 6.5 to 9.2 Pa, while the kinetic constant showed a slightly and negligible reduction. The US increased the juice consistency, whose behaviour was described by the Herschel–Bulkley model. Its yield stress was increased from 2.1 to 3.1 Pa, the consistency index increased from 0.06 to 0.1 Pa.sn, while the flow behaviour index decreased from 0.74 to 0.71. The juice microstructure was evaluated using optical microscopy. The US increased the cell disruption. Whereas the non-treated sample showed whole cells, the treated samples showed a large amount of small particles. These results indicated that the US can increase guava juice consistency, potentially leading to tailor made products with less hydrocolloids and higher consumer acceptability.