Background: Squamous cell carcinoma (SCC) is the third most common cause of oral morbidity in India despite the numerous advances made in the treatment protocol. Aim: To compare the cytomorphometric changes of oral mucosal cells in normal subjects (Group I) with that of tobacco users without any lesion (Group II), tobacco users with oral leukoplakia (Group III), and tobacco users with oral SCC (Group IV) through a semi-automated image analysis system. Materials and Methods: Oral mucosal cells collected from study subjects (n = 100) stained using rapid Papanicolaou stain. Photomicrograph of 50 nonoverlapping cells captured at 50× magnification with a digital image capture system. Cytomorphometric analysis of cells in the captured images was performed with Image-Pro image analysis software. Image analysis was performed to obtain cell diameter (CD), cytoplasmic area (CyA), nuclear diameter (ND), nuclear area (NA), and nuclear-to-cytoplasmic ratio. These values were statistically compared among the groups using one-way analysis of variance (ANOVA) and Mann-Whitney U test. Results: The ND, NA, and nuclear-to-cytoplasmic ratio values were found to be increased in the samples collected from leukoplakia and oral SCC. The CD and CyA decreased compared to the normal mucosa in oral SCC samples. Conclusion: The cytomorphometric changes observed in samples from oral SCC and oral leukoplakia were consistent with the current diagnostic features. Hence, the semi-automated cytomorphometric analysis of oral mucosal cells can be used as an objective adjunct diagnostic tool in the diagnosis of these lesions.