ABSTRACT Signs of oral lesions are one of the initial indications for many major diseases. As we come across different lesions during routine dental checkups, we should be aware about the diseases associated with those lesions. A 47-year-old immunocompetent adult patient reported with small erythematous lesions in the hard palate and small ulcers in the tonsillar pillars and right buccal mucosa with mild pyrexia of 37.8°C. Maculopapular lesions were found on the palms and soles. He was diagnosed with hand-foot-mouth disease, which is caused by the following viruses: Enterovirus-71, Coxsackie Virus (CV)-16, CV-A6, and CV-A10. The severity of this condition leads to meningitis, paralytic polio, and onychomadesis (falling of nails). How to cite this article Devadoss P, Ramesh S, Christopher P, Velusamy A. A Case of Hand-Foot-Mouth Disease observed during Routine Dental Checkup in an Immunocompetent Healthy Adult Patient. J Health Sci Res 2017;8(1):42-45.