Background: End-stage renal disease (ESRD) can impair mineral metabolisms in the human body, such as calcium (Ca), magnesium (Mg), and phosphate (P). Osteopontin is released by the kidneys and inhibits vascular calcification. Examination of the Ca:Mg ratio and Ca x P product in ESRD to see vascular calcification complications and is considered better than a single examination.Objective: To analyze the correlation of osteopontin levels with the ratio of Ca: Mg and product Ca x P in ESRD patients.Methods: Analytic observational study with cross sectional approach was conducted in February-June 2019 involving 30 ESRD patients while hemodialysis at Permata Medika Hospital in Semarang with consecutive sampling. They were screened according to the inclusion and exclusion criteria. Calcium, magnesium and phosphate levels were measured using K lite cornley with the Ion-Selective Electrode (ISE) method. The Ca:Mg ratio and Ca x P product were calculated manually. Osteopontin levels were measured using the ELISA method. Correlation using Spearman test with p<0.05 was considered significant. Results: The median Ca:Mg ratio was 4.63 (3.27 - 5.58) and the Ca x P product was 58.26 mg2/dl2 (19.53 - 111.24). Correlation of osteopontin with Ca:Mg ratio and Ca x P product are respectively with r=0.370 (p=0.044) and with r=0.406 (p=0.026).Conclusion: Osteopontin is correlated to the level of Ca:Mg ratio and Ca x P product in ESRD patients. Latar belakang: Penyakit ginjal tahap akhir (PGTA) dapat mempengaruhi metabolisme mineral, seperti kalsium (Ca), magnesium (Mg), dan fosfat (P). Osteopontin yang dikeluarkan oleh ginjal berfungsi menghambat kalsifikasi vaskuler. Pemeriksaan rasio Ca:Mg dan nilai Ca x P pada PGTA untuk melihat komplikasi kearah kalsifikasi pembuluh darah dan dianggap lebih baik daripada pemeriksaan tunggal.Tujuan: Menganalisis korelasi kadar osteopontin dengan rasio Ca:Mg dan nilai Ca x P pada pasien PGTA.Metode: Penelitian observasional analitik dengan pendekatan potong lintang dilakukan pada bulan Februari-Juni 2019 melibatkan 30 pasien PGTA saat melakukan hemodialisis di RS Permata Medika Semarang yang memenuhi kriteria inklusi dan ekslusi dengan teknik consecutive sampling. Kadar kalsium, magnesium dan fosfat diukur menggunakan alat K lite cornley dengan metode Ion Selective Electrode (ISE) dan rasio Ca:Mg dan Ca x P dihitung manual. Pemeriksaan kadar osteopontin menggunakan metode ELISA. Analisis statistika menggunakan uji Spearman dengan p<0,05 dianggap bermakna.Hasil: Hasil median rasio Ca:Mg adalah 4,63 (3,27 – 5,58) dan nilai Ca x P adalah 58,26 mg2/dl2 (19,53 – 111,24). Korelasi osteopontin dengan rasio Ca:Mg dan nilai Ca x P berturut-turut adalah r= 0,370 (p=0,044) dan r=0,406 (p=0,026).Simpulan: Kadar osteopontin berkorelasi dengan rasio Ca:Mg dan nilai Ca x P pada pasien PGTA.