Early detection and timely treatment of precancerous lesions are hallmarks of successful strategies to prevent deaths due to cancer. Oncolytic viruses are a group of promising anti-cancer agents with wide-ranging experimental and clinical efficacy against solid tumors. Previously, we have shown that NV1066, an oncolytic herpes simplex-1 virus encoding enhanced green fluorescent protein, selectively infects, replicates in, and kills various cancer types. In this study, we sought to determine whether this oncolytic agent can treat precancerous lesions to prevent cancer formation. Using an oral chemical carcinogenesis model in hamsters, we assessed the ability of NV1066 to infect precancerous and cancerous lesions. NV1066 consistently infected dysplastic cells, carcinoma in situ, and squamous cell carcinoma. Animals receiving an intramucosal injection of NV1066 for 7 weeks showed significantly fewer (3-fold) and smaller (4-fold) lesions compared to animals that did not receive viral treatment. Results indicate that infectivity might be dependent on the herpes simplex virus 1 receptor, nectin-1. This study demonstrates that not only can NV1066 treat oral squamous cell carcinoma, but it can also infect and treat premalignant lesions, thus delaying cancer progression. Overall, our study shows the potential of the oncolytic virus NV1066 as a cancer prevention tool.