Abstract: The aim of this study was to evaluate the growth performance of tilapia which were given probiotic, prebiotic and synbiotic through feed. The probiotic bacteria used was selected from Np 1, Np 3 and Np 5. The prebiotic was extracted from sweet potato var. sukuh, while the synbiotic was a combination between a probiotic and prebiotic. This study was conducted in two phases, the in vitro probiotics and prebiotics synergism test and the in vivo feeding trial of selected probiotic, prebiotic and synbiotic to tilapia. The in vivo assays had four treatments with three replications, i.e., (A) control, (B) probiotic 1% (v/w), (C) prebiotic 2% (v/w) and (D) synbiotic (probiotic 1% (v/w)+prebiotic 2% (v/w)). Results of the in vitro assays showed that the three probiotic isolates could grow in media containing the prebiotics and Np 5 isolate demonstrated the best growth. In the in vivo assays, the application of the synbiotic resulted in the best growth rate, feed efficiency, digestive enzyme activity, feed digestibility and nutrient retention compared to the control and the other treatments.