The myelodysplastic syndromes are a heterogenous group of hematologic disorders of myeloid progenitor cells. Oral manifestations may be among the first signs and often reflect degrees of neutropenia or neutrophil dysfunction. A patient with persistent herpes labialis and severe oral mucosal ulceration in myelodysplastic syndrome is reported. The features of myelodysplasia are reviewed and their oral manifestations and significance to dental management outlined.