TheStreptococcus agalactiaeoutbreak in tilapia has caused huge losses in the aquaculture industry worldwide. In Malaysia, several studies have reported the isolation ofS. agalactiae, but no study has reported the isolation ofS. agalactiaephages from tilapia or from the culture pond. Here, the isolation of theS. agalactiaephage from infected tilapia is reported and it is named as vB_Sags-UPM1. Transmission electron micrograph (TEM) revealed that this phage showed characteristics of aSiphoviridaeand it was able to kill two localS. agalactiaeisolates, which wereS. agalactiaesmyh01 and smyh02. Whole genome sequencing (WGS) of the phage DNA showed that it contained 42,999 base pairs with 36.80% GC content. Bioinformatics analysis predicted that this phage shared an identity with theS. agalactiaeS73 chromosome as well as several other strains ofS. agalactiae, presumably due to prophages carried by these hosts, and it encodes integrase, which suggests that it was a temperate phage. The endolysin of vB_Sags-UPM1 termed Lys60 showed killing activity on bothS. agalactiaestrains with varying efficacy. The discovery of theS. agalactiaetemperate phage and its antimicrobial genes could open a new window for the development of antimicrobials to treatS. agalactiaeinfection.