Nowadays, the use of rodenticides either in housing or office is increasing. We can find many type of rodenticides with its own effectiveness in order to control rats. Rats cause economic, social and especially health problems for human. Because of that problems, rodenticides is one of the solution in controlling rats population. Despite of the decrease number of rats, still we have to take serious concern about its adverse effect for human and environment. In general, rodenticides are divided into two groups, that works with slow and fast action for the target rats. Contrac 0,005 is one of anticoagulant group and has Bromadiolone as an active material. The aim of this study is to determine an effective dose of Contrac 0,005 against White Rats and its contact time for rats. White rats divided into 6 treated groups with one group as a control. The result shows that an effective dose of Contrac 0,005 was 300-400 mg and 72-96 hours as the exact contact time. The research factors such as eating time, rats resistant and the body metabolism need to be study further.