Reid's Colposcopic Index (RCI) is a systematic, objective method of colposcopically grading the severity of premalignant cervical lesions. The index considers four colposcopic signs: lesion margin, color of acetowhitening, blood vessels, and iodine staining. The RCI can accurately predict the histologic grade of cervical disease, readily permitting differentiation between low-grade cervical disease and high-grade disease. Hence, use of the index helps direct the clinician to perform a biopsy of the most significant abnormal cervical lesions and enhances the formulation of the colposcopic impression.