Guava seeds powder (GSP) is rich source of dietary fiber, minerals, and antioxidants compounds. The present study was administered to evaluate the effect of supplementation with GSP on the physicochemical, rheological, and sensory properties of probiotic low-fat yoghurt. GSP was added at ratios of 1, 2, and 3%. A gradual increase in dietary fiber, Acidity, viscosity, total phenolic content, and antioxidant activity was recorded in GSP-enriched yoghurt as the GSP ratio increased. On the other hand, the pH values and syneresis were decreased in GSP enriched yoghurt when the ratio of GSP increased. Low fat yoghurt supplemented with 3% of GSP had the best physicochemical, acceptability, sensory and rheological properties. In all treatments bacterial counts increased in GSP-enriched yoghurt treatments. The study demonstrated that GSP might be used as a source of phenols and dietary fiber in low-fat yoghurt and that enhances its nutritional value and its rheological and sensory properties. GSP contain fiber, and thus have been suggested to fulfill the prebiotic concept, and that led to an increase in the counts of probiotic bacteria in manufactured treatments to exceed about 106 CFU/g. thereby acting as prebiotics, and the produce low-fat yoghurt supplemented with GSP as synbiotic.