Purpose To assess p53 gene expression in pterygia with and without recurrence. The pathogenesis of pterygium has not yet been determined. The most widely recognized etiologic factor is ultraviolet radiation, which leads to degeneration of the conjunctiva. However, pterygium was recently found to have several tumor-like characteristics. The p53 gene is a common marker for neoplasia, and is known to control cell cycle, cell differentiation and apoptosis. In this study we examined the expression of the p53 gene in primary pterygia with and without recurrence, searching for the pathogenesis of this very common lesion and for a prognostic factor for recurrence.