Hand-washing is a process of removing the dirt and debris from skin of both hands mechanically by using soap and running water. The purpose of hand-washing is removing the dirt and organisms from the skin and reducing the microbes. There are some styles on hand-washing. One of them is the style according WHO guidelines presented in English language. The study was conducted to describe the knowledge level based on the understanding through a language of health students at Universitas Muhammadiyah Magelang on hand-washing tool according to WHO guidelines and the behaviour on it. The method used was descriptive analytic research by distributing a questionnaire to respondents revealing the knowledge and behaviour level of health students about hand-washing. The samples were 124 health students taken by random sampling technique. The data were presented as percentage of frequency distribution. This study showed the knowledge level on hand-washing tool according to WHO guidelines with category of less for 15,33%, good for 55,64% and very good for 29% while the behaviour level with category of very less for 27,41%, less for 43,54%, good for 20,2% and very good for 8,85%. So, this study showed that the students in aged 17-20 have a good level of hand-washing knowledge with a percentage of 51.6%. Another result of this study showed majority of the knowledge level on hand-washing tool according to WHO was good for 55,67% but inversely proportional with the behaviour level in category less for 43,54%