<h3>Background</h3> DNA ploidy analysis is arguably the most sensitive and reproducible approach to assess risk in oral potentially malignant disorders. Although aneuploidy has been associated with a high risk of malignant transformation (MT), the current diagnostic criteria of aneuploidy are not specific to oral mucosal tissues and thus yield positive predictive values (PPVs) ranging from 30% to 40%. <h3>Objective</h3> The aims of this study were to analyze the ploidy status of archived material diagnosed as oral leukoplakia (OL) with follow-up data on MT and to review the risk classification criteria. <h3>Methods</h3> Nuclei suspensions were enzymatically prepared from formalin-fixed, paraffin-embedded tissue from 121 patients with OL and stained with propidium iodide for flow cytometry. Twenty-three patients had MT. Histograms were initially analyzed for the proportion of nuclei in G<sub>1</sub> phase (2c), S phase, G<sub>2</sub> phase (4c), and 5c-exceeding rate (5cER). Histograms diagnosed as aneuploid were further investigated qualitatively on the basis of nuclei distribution pattern. Log-rank test on Kaplan-Meier curves (LRKM; <i>P</i> < .05) as well as sensitivity (SS) and specificity (SP) were calculated for both traditional aneuploidy-based risk (TAR) and enhanced aneuploidy-based risk (EAR). <h3>Results</h3> Seven aneuploid histogram types were detected, of which only 3 proved truly high risk. EAR was then stratified as low risk (diploid), medium risk (low-risk aneuploid), and high risk, whereas TAR remained as diploid (low risk) and aneuploid (high risk). Aneuploidy in TAR had PPV of 55%, SS of 88%, and SP of 81% (LRKM <i>P</i> < .0001). High risk in EAR showed PPV of 79%, SS of 82%, and SP of 94% (LRKM <i>P</i> < .0001). <h3>Conclusions</h3> Enhancement of TAR based on qualitative histogram classification significantly improves predictive values. Flow cytometry is an accessible approach to assess MT risk in OL.