Surgery is one of medical procedures that can be a stressor causing anxiety in patient. In Mamuju district hospital, informed consent is considered as medical procedure.This study was aimed to determine the influence of informed consent provision towards the level of anxiety in pre-operative patients at Mamuju District Public Hospital. The population in this study was pre-operative patients. Accidental sampling approach was applied to obtain a total of 32 samples. This quantitative study used quasi experimental design with a non-equivalent time sample design which was analysed using the Wilcoxon statistical test. The results showed that there was the effect of provision of informed consent on the level of anxiety in pre-operative patients at Mamuju District Public Hospital. Informed consent can reduce anxiety in pre-operative patient at Mamuju District Public Hospital.