Background : The habit to protect cleanliness of the genital area (perineal hygiene) is a woman's initial attempt to maintain the health of reproductive organs. Perineal hygiene is done to maintain cleanliness and prevent perineal infections and provide comfort. The different source of knowledge about perineal hygiene during menstruation, give a different understanding. From some interview was found that some female student has disruption of perineal, like itching during use sanitary pads, brownish yellowed of whiteness and pain feeling. Purpose: To find out the description of first-level nursing student knowledge about perineal hygiene during menstruation. Research Method: This research uses a quantitative descriptive method and using Total Sampling method for 302 nursing students from the Western Private University of Indonesia. Instrument of this study is form of a questionnaire with 15 questions. Results: The results of the univariate analysis showed 62 (20%) of respondents had a good level of knowledge, 147 (49%) of respondents had sufficient knowledge and 93 (31%) of respondents had a level of lack of knowledge. Conclusion: The knowledge level of female students is calculated using excel computer system and written in three categories of knowledge level, there are good, fair and less. From the result that has been obtained conclude that, the dominant respondents in this study have fair level of knowledge. Suggestion: The next authors is expected to research about the coherency beetween level of knowledge and perineal hygiene during menstruation.