Colposcopy is an important secondary screening method to triage women needing biopsy for the diagnosis of cervical cancer. Different scoring systems have been introduced for the standardization of colposcopic variables’ grading. The main variables are acetowhite uptake, cervical vasculature, and extent of involvement. Iodine staining and lesion size have also been used in the Reid scoring system and Swede score respectively. This study compares the diagnostic performance of the Modified Swede Colposcopic Index (MSCI) and Swede score for premalignant and malignant lesions to histopathology. This study was carried out in 150 women visiting AIIMS Deoghar OPD in Jharkhand after obtaining ethical clearance. The women with a history of postcoital bleeding, postmenopausal bleeding, and persistent discharge per vagina with unhealthy looking cervix were screened. The women with positive reports of Pap smear screening were included in the study after informed consent. Pregnant women, women with frank growth on the cervix, and women diagnosed and treated for cervical cancer were excluded. Colposcopy-guided biopsy samples were obtained from them and sent for histopathology. The results were recorded and analyzed. The sensitivity, specificity, PPV, and NPV of MSCI threshold score 9 for CIN2 and higher lesions were 96.55%, 68.07%, 51.38%, and 98.26% with an AUC of 0.718 (0.639–0.788 95% CI). The sensitivity, specificity, PPV, and NPV were calculated as 74.14%, 65.66%, 43%, and 87.9% for threshold Swede score 5 with an AUC of 0.630 (0.547–0.707 95% CI). The difference between the two ROC curves was significant with a p-value of 0.0015. The diagnostic efficacy parameters of MSCI were significantly better than the Swede score in this study. The omission of iodine staining and inclusion of easily measurable location and quadrant involvement lead to increased diagnostic performance of MSCI.