AbstrakTujuan: Membandingkan penanda tumor osteopontin (OPN), cancer antigen 125 (CA125), kombinasi sebagai prediktor keganasan pada penderita tumor ovarium. Metode: Penelitian cross sectional ini dilakukan pada pasien dengan keganasan pada kista ovarium jenis epitel. Analisis data dilakukan secara univariat dan bivariat. Hasil: 47 pasien dengan hasil hitopatologi jinak dan 43 dengan hasil histopatologi ganas masuk dalam penelitian. Hasil nilai median CA125 kelompok ganas dibanding kelompok jinak (142,2 vs 61,030, p < 0,05), cut off point CA125 99,9 U/mL, sensitivitas 76,7% dan spesifisitas 61,7%. Diskusi: Kombinasi CA125 dan OPN memiliki sensitivitas lebih rendah dibandingkan CA125. Kombinasi CA125 dan OPN akan meningkatkan spesifitas, nilai duga positif dan akurasi yang lebih baik. Tumor marker OPN tidak tepat digunakan untuk proses deteksi dini, tetapi lebih tepat untuk penegakan diagnosis lebih baik dibandingkan dengan gold standard CA125.Kesimpulan: Kombinasi OPN dan CA125 memiliki nilai tingkat akurasi paling tinggi apabila dibandingkan pemeriksaan tunggal CA125, OPN. Single Check of Serum Ostepontin and CA 125 Levels as A Predictor of Malignancy in Epitheliaal Ovarium Tumor is Inferior to Combined ExaminationAbstractObjective: To compare the sensitivity, specificity, expected value positive, expected value negative and accuracy among osteopontin (OPN), cancer antigen 125 (CA125), and combination as predictor of malignancy in ovarian tumor patients.Method: A cross sectional study was done to compare parameters OPN and CA125 in determining malignancy of ovarian cysts. Data analysis was performed by univariate and bivariate analysis. Results: A total of 47 subjects were included with benign histopathological result and 43 subjects with malignant histopathological result. The median value of CA125 in malignant group was compared to that of benign group (142.2 vs. 61.030, p value <0.05), the cut-off point of CA125 was 99.9 U/mL with sensitivity of 76.7% and specificity of 61.7%. Discussion: Combination of CA125 dan OPN has lower sensitivity compared to single tumor marker CA125. This combination will increase specificity, positive predictive value and accuracy. The OPN is inappropriate when used for early detection instead is suggested for diagnostic value risk predictor for malignancy in ovarian tumor compared to gold standard CA125.Conclusion: Combination OPN dan CA125 has higher accuracy compared to single CA125, and OPN. OPN was useful biomarker for predicting ovarian malignancy.Key words: Epithelial ovarian tumor, OPN, CA 125, predictor for ovarian malignancy