W Waterflooding has been conducted in “X” Field since 1996. In 1999, injection has been fully implemented and until now there are 10 active injection wells. Waterflooding is used to push the remaining oil in reservoir in order to produce the oil. Some specific evaluations are needed to ensure the success of the waterflood implementation. There are three aspects that will be evaluated. They are Hall Plot method to determine reservoir condition, Buckley-Leverett method to evaluate the water time breakthrough, and Pattern & Balance method to find the optimum injector capacity for each injection well. The Hall Plot is done for a pair of injection and disposal well in each layer. The Buckley-Leverett method modified by Welge evaluate the breakthrough time of a pair injection well and production well. The Pattern & Balance method figures the optimum injection rate from the last production data. In the Hall Plot method evaluation almost all of the injection wells are stable. The Modified Welge method concludes the fastest water breakthrough time is 32 days and the longest one is 33,710 days (93.6 years) with highest oil production at 898,474 STB at breakthrough. The Pattern & Balance analyses result for injector capacity in some wells are less than the estimated, while some others are more than the estimation. In conclusion, waterflooding in this field is successful in the evaluation using Hall Plot method, even though it requires some of the injectors to be adjusted in their injector capacity