This descriptive study was performed to defermine the behaviour on menstrual and perineal hygiene of students in three primary schools of Alibaba health center district in Sivas. The universe of the study was made up of a total of 139 female students from the three schools, who had menstruation. The universe of the study was included in the study totally. The age of the students varied between 9 and 17. Data was collected in April-May 2004 through a questionnaire developed by the researchers and evaluated by creating a data base using SPSS software program. Parents of most of the students had graduated from primary school (43.9 % of mothers and 41.0 % of fathers). 74.1 % of students lived in nuclear families, and insurance of 37.4 % of them vas Social Insurance Institution. The study revealed that 15.1 % of the students did not take a bath during menstruation. The study also revealed that 23.7 % washed the perineal area from behind to front, 15.1 used washed cotton material, about one third of them (28.0) changed their ped one or two times in a day, one fifth (22.3 %) of students changed their underpants once a week, and only 12.9 % changed their underpants every day. It can be concluded from these results that the hygienic behaviour of students relating to perineal and menstruation hygiene is not sufficient, causing a risk for infection.