Abstrak-Singkong kaya akan karbohidrat akan tetapi mengandung asam sianida (HCN), sedangkan biji pepaya mengandung flavonoid, tanin dan saponin yang bermanfaat bagi kesehatan. Cara meningkatkan nilai jual singkong dan biji pepaya dengan mengolah susu singkong termodifikasi dengan metode awal, yaitu singkong yang telah dibersihkan, direndam 72 jam dengan 4% w/v NaHCO3, direndam 1 jam dengan 15% w/v garam, direndam 24 jam dengan 0,1% w/w starter Bimo-Cf, lalu diaduk pada suhu 75- 80 oC dan fermentasi selama 3 hari menggunakan Fermipan (Saccharomyces cerevisiae) dan Raprima (Rhizopus oryzae). Hasil fermentasi ditambahkan aquadest dan biji pepaya (20 dan 40% w/w) diaduk pada suhu 70-75 oC. Hasil penelitian menunjukan penurunan kadar HCN lebih besar pada susu singkong termodifikasi dengan penambahan 40% w/w biji pepaya pada Saccharomyces cerevisiae (2,052 ppm) dan Rhizopus oryzae (2,160 ppm). Kenaikan kadar protein terbaik diperoleh dengan penambahan 40% w/w biji pepaya pada Rhizopus oryzae (4,06%) dan Saccharomyces cerevisiae (3,30%). Hasil penelitian menunjukan bahwa penggunaan ragi merk Fermipan dan Raprima yang harganya murah dan non patogen serta dengan penambahan biji pepaya mampu menurunkan kadar HCN dan sekaligus meningkatkan kadar protein. Semakin banyak penambahan biji pepaya semakin besar penurunan kadar sianida dan semakin tinggi kadar protein. Perlakuan terbaik didapatkan pada penambahan 40% biji pepaya. Kata Kunci: Biji pepaya, Detoksifikasi HCN, Rhizopus oryzae, Saccharomyces cerevisiae, Singkong. Abstract-Cassava is rich in carbohydrates however it contains cyanide (HCN), while the papaya seeds contain flavonoids, tannins and saponins that are beneficial for human. One way to increase the value of cassava and papaya seeds is by processing milk cassava modified by the initial method, namely cassava that had been cleaned, soaked for 72 hours with a 4% w/v NaHCO3, it then soaked for 1 hour within 15% w/v NaCl, soaked again for 24 hours with 0,1% w/w starter Ben-Cf, then it stirred at 75-80 °C and fermented for 3 days using Fermipan (Saccharomyces cerevisiae) and Raprima (Rhizopus oryzae). It was fermented and distilled water was added as well as papaya seeds (20 and 40% w / w), it was stirred at 70-75 °C. The results showed decreased levels of HCN was greater in milk cassava modified by the addition of 40% /w of papaya seeds in Saccharomyces cerevisiae (2,052 ppm) and Rhizopus oryzae (2,160 ppm). The increase in protein content is best obtained by the addition of 40% w/w of papaya seeds on Rhizopus oryzae (4.06%) and Saccharomyces cerevisiae (3.30%). The results showed that yeast (Fermipan and Raprima as cheap brands and non-pathogenic) with the addition of papaya seeds can decrease HCN content and simultaneously increase the protein content. The more the addition of papaya seeds the greater the reduction of cyanide content and higher the protein content. The best result was obtained on the addition of 40% of papaya seeds. Keywords: papaya seeds, Detoxification HCN, Rhizopus oryzae, Saccharomyces cerevisiae, Cassava.