AbstrakResistensi insulin merupakan penurunan respons biologis jaringan terhadap insulin dalam kadar normal. Pada DM tipe 2 terjadi resistensi dan gangguan sekresi insulin. Terdapat indeks baru 20/(C-peptide puasa x glukosa darah puasa) untuk menilai resistensi sekaligus gangguan sekresi insulin. Penelitian bertujuan membuktikan korelasi indeks 20/(C-peptide puasa x glukosa darah puasa) dengan HOMA-IR untuk menilai resistensi insulin pada DM tipe 2 di RSUP. Dr. M. Djamil Padang. Dengan menggunakan sampel darah dari pasien, kadar glukosa darah puasa, insulin puasa dan C-peptide puasa ditentukan. Data yang diperoleh kemudian dianalisis menggunakan korelasi Pearson. Hasil penelitian menunjukkan rerata kadar glukosa puasa 9,83 (3,53) mmol/L [177 (63,54) mg/dL], insulin puasa 10,58 (3,61) μU/L, dan C-peptide puasa 0,97 (0,29) nmol/L dan terdapat korelasi yang sangat kuat dan bermakna secara statistik (p<0,0001) antara indeks 20/(C-peptide puasa x glukosa darah puasa) dengan HOMA-IR (r= -0,838). Dapat disimpulkan bahwa indeks 20/(C-peptide puasa x glukosa darah puasa) dan HOMA–IR berkorelasi kuat untuk menilai resistensi insulin pada DM tipe 2 di RSUP. Dr. M. Djamil Padang.AbstractInsulin resistance is a decrease of biological response of the tissues to the normal level of insulin. In type 2 diabetes, there is resistance and impaired of insulin secretion. There is a new index available to assess resistance and impaired of insulin secretion all at once, with the formula 20/(fasting C-peptide x fasting blood glucose). This study aimed to prove the correlation of this new index to the HOMA-IR (Homeostasis model assesment of insulin resistance) in type 2 diabetes at Dr.M.Djamil Padang hospital. Level of fasting glucose, fasting insulin and fasting C-peptide of blood were measured, followed by statistical data analysis using Pearson correlation test.The result showed the mean of fasting blood glucose, fasting insulin and fasting C-peptide were 9.83 (3.53) mmol/L[177 (63.54) mg/dl], 10.58 (3.61) μU/L, and 0.97 (0.29) nmol/L respectively.There was a strong and statistically significant correlation (p<0.0001) found between the new index and the HOMA-IR ( r= -0.838). To be concluded, the index 20/(fasting C-peptide x fasting blood glucose) and HOMA-IR was strongly correlated to assess insulin resistance in type 2 diabetes at Dr. M. Djamil Padang hospital