Latar Belakang : Remaja putri rentan terhadap anemia karena mengalami menstruasi, dalam fase itu zat bezi sangat diperlukan. Pengetahuan sangat berpengaruh dalam pencegahan anemia selama masa menstruasi. Menurut Dinas Kesehatan Provinsi Bali kejadian anemia 5,07% pada tahun 2019, meningkat 5,78% pada tahun 2020. Tujuan : Untuk mengetahui Tingkat Pengetahuan Remaja Putri tentang Pencegahan Anemia Selama Masa Menstruasi di SMK Negeri 1 Klungkung. Metode : Deskriptif dengan pendekatan cross-sectional study. Teknik non-probability sampling, yaitu total population sampling. Jumlah sebanyak 173 responden siswi kelas X di SMK Negeri 1 Klungkung. Pengumpulan data menggunakan kuesioner selama 1 hari. Hasil : Penelitian yang sudah dilakukan mendapatkan hasil kategori baik sebanyak 127 responden (73,4%), kategori cukup sebanyak 44 responden (25,4%), dan kategori kurang sebanyak 2 responden (1,2%). Namun 2 pernyataan mendapatkan jawaban benar paling rendah sebanyak 100 responden (57,8%) dengan pernyataan sumber makanan hewani yang mengandung zat besi dan sebanyak 97 responden (56,1%) dengan pernyataan konsumsi tablet zat besi (Fe) selama masa menstruasi. Kesimpulan : Karakteristik responden berdasarkan usia sebagian besar berusia 16 tahun 103 responden (59,5%). Mayoritas memiliki kategori pengetahuan baik sebanyak 127 responden (73,4%). Dan kategori pengetahuan kurang sebanyak 2 responden (1,2%). Disarankan meningkatkan pengetahuan dan wawasan mengenai pencegahan anemia selama masa menstruasi. Kata Kunci : Tingkat Pengetahuan, Anemia, Menstruasi

Background: Adolescent girls are susceptible to anemia due to menstruation. Knowledge is very influential in preventing anemia during menstruation. According to the Bali Provincial Health Office, the incidence of anemia was 5.07% in 2019, increasing to 5.78% in 2020. Aim: This study aimed to find out the level of knowledge of adolescent girls about preventing anemia during menstruation in the Public Vocational School 1 Klungkung. Methods: Descriptive with a cross-sectional study approach. 173 female students of class X involved in this study were gained through total sampling. The data were collected using a questionnaire in one day. Results: The results showed that 127 respondents (73.4%) had good knowledge, 44 respondents (25.4%) had sufficient knowledge, and only 2 respondents (1,2%) had poor knowledge about preventing anemia during menstruation. 2 questions that mostly incorrectly answered by the students were: 1) animal food sounrces containing iron (100 respondents; 57.8%), and 2) consumption of iron tablets (Fe) during menstruation (97 respondents; 56,1%). Conclusion: The majority of respondents were aged 16 years (103 respondents; 59.5%), have a good knowledge (127 respondents; 73.4%), and only 2 respondents (1,2%) who have a poor knowledge about anemia prevention during menstruation. Students are recommended to increase their knowledge and insight regarding the prevention of anemia during menstruation. Keywords: level of knowledge, anemia, menstruation