Background: Washing hand is very important to do especially for everyone in primary health care. Washing hand is one of the preventive ways to prevent nosocomial infection or Healthcare Associated Infections, so that the visitor’s knowledge about hand washing is important. Based on Riskesdas data in 2007, especially in Bantul regency Yogyakarta only 46.3% people who behaves right in hand washing. Smaller than the other areas in Yogyakarta. Purpose: To analyze the influence of educating with mnemonic method to increase knowledge about hand washing in Kasihan I and Sewon I Bantul’s primary health care. Method: This is a quantitative research with quasy experiment pretest-posttest control group design. The sample is primary health care’s visitor at Kasihan I and Sewon I while the respondents are 60 of it. They are collected by an accidental sampling technique. Paired Sample T-Test is used to analyze the relations between both variables. Result and discussion: There are significant differences between experiment and control group (p=0.001). So, educating with mnemonic’s method is evidently effective to increase knowledge about hand hygiene. Conclusion: The result of this study indicates that educating with mnemonic’s method can increase people’s knowledge about hand washing.