The study of biomarkers by immunohistochemistry (IHC) for cervical cancer and intraepithelial lesions is a promising field. However, manual interpretation of IHC and reproducibility of the scoring systems can be highly subjective. In this article, we present a novel and simple computer-assisted IHC interpretation method based on cyan-magenta-yellow-black (CMYK) color format, for tissues with diaminobenzidine cytoplasmatic staining counterstained with methyl green. This novel method is more easily interpreted than previous computer-assisted methods based on red-green-blue (RGB) color format and presents a strong correlation with the manual H-score. It is simple, objective, and requires only low-cost software and minimal computer skills. Briefly, a total of 67 microscopic images of cervical carcinoma, normal cervix, and negative controls were analyzed in Corel Photo Paint X3 software in CMYK and RGB color format, and compared with manual H-score IHC assessments. The clearest and best positive correlation with the H-score was obtained using the image in CMYK color format and crude values of magenta color (Spearman correlation coefficient=0.84; agreement of 93.33%, P<0.001). To obtain this value, only 3 steps were necessary: convert the image to CMYK format, select the area of interest for analysis, and open the color histogram tool to visualize the magenta value.